I am following with great interest although I know I'll probably never have the time to have such a complicated setup.

All of that being said, WRT nitrite levels and water changes,

If you know the concentration of nitrite, shouldn't you be able to bring it to a target value by doing a specific number of serial water changes?

I have no idea how much volume you can exchange at one time, but it seems like you could solve the equation:

(1) Nitrite concentration as % of starting = e^(-(percent water changed each time)*(number of water changes))

in order to target a specific nitrite concentration.

As a purely practical matter, I have no idea how much volume change (as a percent) you can do each time?

eta: OBVIOUSLY this assumes that the fresh water has zero % nitrite, you have to modify the exponential decay curve to account for nitrite in the fresh water if it has any appreciable amt

Ammonia, nitrite and nitrate levels in the well-water are undetectable/zero.

In my readings and from what I’ve encountered so far in my two systems there are several issues that come up with water changes whether doing it for ammonia, nitrite, nitrate or algae:

1)      The water used to make changes ideally should be as near the same temperature as the water in the system.  My well water is cold.  I just measured it again for this post (lunch break!) and it’s at 52F.  The temperature drop can be mitigated by only doing small volume changes, but if you need the nitrites to come down more quickly then the large volumes can drop the temperature a lot.  To recap, the 3 living organisms you are worried about are:

A) Plants:  They usually are the most tolerant of drops in temperature.  But you’ll even see posted in this sub-forum that cold well water should be allowed to warm up before using it to water plants as it can and does ‘shock’ them.  These are not tropical plants but I would still like to avoid anything that stresses the plants and makes them less capable of absorbing nitrogen in the form of ammonia and more importantly nitrate.

B) Fish:  These are probably a little less tolerant of significant temperature drops than the plants.  With trout, though, I’m not too worried since they are a very cold water loving species.  I’ll even use the hose with the narrow spray to get some extra oxygen into the water which I think they like when doing water changes.

C)  Nitrogen processing bacteria:  These are the least tolerant of temperature drops.  They prefer temperatures in the 70’s and 80’s, or at least that is their ideal operating temperature.  They still metabolize ammonia and nitrite below that, but there is a measurable decrease in their ability to process waste as the temperature drops.  Doing a big water change where the temperature precipitously drops down by 15 or 20F is definitely going to drop their metabolic rate.  So you may get rid of extra nitrite, but then have a potential build-up of ammonia because the bacteria are not processing it as fast.  If you’re careful not to change out large volumes than you should be ok.

2)      When you remove water from the system (other than by evaporation) then you remove the good with the bad ie. throwing the baby out with the bathwater.  Both micro and macronutrients that  are not harmful to the fish get thrown out as well.  All the minerals like magnesium, calcium, phosphate, potassium etc. that end up in the water from the fish digesting and processing foods gets removed from the system.  These are used by the plants so losing them can potentially adversely affect their metabolism and growth, thereby leading to an increase in nitrate.  

If you salt your tanks then that also has to be replaced.  The plants do need some salt.

I’m also using barley extract which inhibits algae growth so I have to add more if I do big water exchanges.  

Ideally, the only water that you should be replacing is that lost by evaporation.  Obviously in the beginning that is not possible since there will be spikes in either ammonia or nitrite or nitrate that have to be dealt with or you will kill your fish.  I’m still doing some water changes in the small system since the nitrates are still a little high.  But I’m keeping the volume of changes low and daily so temperature is not dropping much.  I’m using the nitrate-laden water for watering my soil plants.  I measured the ammonia yesterday and it’s barely detectable and the nitrites were zero.  So hopefully as the tomatoes and other plants grow I won’t have to do any water changes because of the nitrates.

More later.

I reconnected the 500 gallon fish tank with the rest of the system tonight.  I'm using a 1900 gallon-per-hour Tetra pond pump that I've spliced a ball valve into the vinyl tubing and I can adjust the flow.  The temperature is 68F in both the fish tank and the sump tank.  This is a great temperature.  Hopefully oxygen levels are good.  I took one of the medium pumps and it has a short garden hose attached to it.  It takes water from the bottom of the fish tank and brings it to the top and creates good turbulence and hopefully good oxygenation.  

If it cycles well overnight and everything looks good in the morning, I may try to pick up more trout tomorrow.  I'm not sure on the number of fish, but I'm going to go with the smaller 6" size.  I'm also not sure on the type, whether I'll just do Rainbows again or a mix of Rainbows and Brown Trout.  

I'll update tomorrow..

I upgraded a few things in the system and mentioned it in earlier posts.  The water return hose is on the left.  It brings water back from the sump tank.  On the right, you can see the light green short garden hose that is attached to a pump that brings water from the bottom of the fish tank to the top.  Notice that the top of the outflow pipe has been modified.  It's a "T" junction so that an obstruction at the bottom of the PVC tube at the bottom of the tank can be by-passed through the top.  This way the whole tank doesn't overflow.



Here the water pumps have been turned on.  There's good flow but not too much since the return hose is adjustable.  The second pump really churns up the water and adds a lot of oxygen.



The return hose is covered by black pipe insulation almost it's entire length to prevent algae build-up.



I spliced a PVC ball valve so I can make gross adjustments to the water flow out of the sump tank pump.



I'm planning on getting a bunch of large crawfish/crayfish for the bottom of the tank.  I have two traps and I'm going to set them up in a local pond that is full of them.  I only have this one and he loves it in there!



These small ones (pic #1) are going into the smaller system's sump tank along with some baby blue channel catfish (pic #2).





The grow bed is filling up nicely with plants.  I still want to put more tomatoes in there.  I hope they all survive.



I have 500 gallons of water in the big tank and about 250 to 275 in between the sump tank and grow bed at any one time for a total of 750 to 775 gallons.  Using 750 gallons, I found a good thread on Backyardaquaponics.com and calculated 3 pounds of salt in 750 gallons gives 0.5 ppt (part per thousand).  I wrote that I was going to do 1 ppt but chickened out.  I will likely add the second 0.5 ppt in a few days if everything goes well.  The salt:



The Rainbow Trout.  These are probably between 6 to 7 inches, maybe 8".  They're a good bit smaller than the previous ones but I have 12 of them.  The total weight is well below what I had before so I'm not too worried.  But I will be even more vigilant this time around.



Temperature in the fish tank was 72F.



I got the cooler with the fish slowly up to 68F since that's close enough not to shock them when they are transferred.





And awaaaaay we go!

First off Great job so far.

Random thoughts from my reading.   These thoughts are all based on aquaculture/aquarium/ornamental pond experience i have over the years.  I hope they can in some way help the current and/or future stockings.  

We usually use about 1 # salt per 100 gal water as a bath.  we water change out the salt after its served its purpose, it has to much of a negative effect on the plants ( ornamental in my experience not veggies).
Watch the new fish very closely,  you did not sterlize the system, so there may still be bad fungus or bacteria that killed the last batch present and waiting for a new host,  ie your new trout.
QUARANTINE all new additions.
Sterilize or let the system run fallow with out fish for 4-6 weeks or longer if not sterlizing to prevent old diseases/issues to get on new fish
On your ball valve,  you will kill the pump life by putting that kind of back pressure on it, you need a bypass  that is a  T with a valve putting water back into the sump and valving that extra water to provide the correct flow to the tank.      sump    =>  hose =>   T   => to tank  
                                                                      /\                            \/
                                                                        ––––-   hose  <= Valve      you dont want to restrict the main flow unless there in a manifold system then all branches get a valve so they can be controlled, preferably with a bypass also for any possible extra water.

Bug Zapper over tank= free food no work  
Adding substrate from a local pond adds good and bad  that is bacteria parasites fungus etc. Also these can hitch hike in on the crayfish, plants etc.  see above  Quarantine.  
Prime by seachem is great at detoxifying  NH3,NO2 and NO3 still available to the bacteria and wont screw up your test results as some others do.
Flush the water through if having issues if needed,  slow steady addition from your well not a drop and fill  ie continuous water change.  Or  have another tub full of water to the side so you can dump and fill the tank then refill the extra tank so it comes up to temp and is ready for next time.
.5 NH3 can be deadly.
Algae will only consume oxygen at night or in the dark, ( and make CO2)   they produce O2  during the day = photosynthesis   watch your Ph it will swing with the day night cycle.  C02 increases at night and drops Ph.
   Algae can be your friend used correctly.  
Pond perfect is awesome stuff from TLC  on starter cultures
For every 10* drop C bacterial metabolism decreases by 50%  Not that they dont work they just do it slower, they will ramp up as quick as the temp moves back up
The bacteria will tolerate (More and larger and not get sick ) better then the fish the temp  fluctuations     ie Ick/Ich  the most common, more so with drop then increase in temps    also watch for  fungus or  bacterial infections.   The fish are the least tolerant of the temp swings then the plants or bacteria.   Your sheen on the fish may have been bacterial, as fungus looks like cotton balls.  
Lower the temp the more O2 it can hold
bacteria stop metabolizing NH3 around a Ph of 5.8.  

Your T for the overflow    Put a cap on it with a bunch of holes drilled in it or a strainer, something will some how fall/lodge in there and stop up the drain, ask me how i know.  
Did you acclimate the fish?  there is a process that make the transition easier on them      The below is written for saltwater but is the same process.  

We always recommend quarantining your fish for a minimum of 2 weeks prior to placing them in a show aquarium.
Place fish into a clean bucket with all packaging water.
Use air line tubing to siphon water from the tank into the bucket at a rate of 1-5 drops/sec depending on the volume of original water. A loose knot can be tied in the air line tubing to regulate the water flow.  If large volume of water have it run at a faster drip or a full siphon with the airline.  
Let the water volume at least double preferable more and make sure the salinity's are identical before preceding.  This should take about 20-40 minutes.
* As you are acclimating, you can use a profolactic dip such as Paraguard at 3ml/gal for the removal of possible external parasites.
Turn off lights to reduce aggression from dominate tank mates. Remove fish from bucket and place into tank.  If aggression is occuring feed the tank to allow the new fish time to find refuge.
Discard water in bucket and top off tank with new saltwater.

Im done for now its 2 am  

leoismydog,


First, thank you for all the advice.  I do want to add some comments and I'll do it in another post below, but I have a question regarding the pump issue specifically:

The pump outflow has an adapter that needs a 1 1/4" internal diameter tubing to slip over it.  I then use a pipe clamp over the tubing to secure it well to the pump outflow adapter.  Since the tubing goes on the outside of the adapter coming out of the pump, it means that the adapter's internal diameter must be less than 1 1/4".  The way I've attached the ball valve is by using a 1" ball valve meaning it accepts 1" internal diameter PVC tubing which is glued to both ends of the ball valve.  It just so happens that the 1" PVC tubing fits snuggly inside the 1 1/4" vinyl tubing.  

My plan from the advice you've given is to use a 1" T junction which accepts 1" internal diameter PVC tubing, slip the 1 1/4" internal diameter vinyl tubing over it, secure it with pipe clamps, and then attach the ball valve off of the T junction and have this water flow back into the sump tank.

Is this enough to keep the pump happy and live a long time?  Basically, there should be 1" internal diameter tubing throughout which should be close to the internal diameter of the pump outflow adapter.

Yes  that sound correct.

The inside diameter matters but the 1 ' restriction you have i dont think is an issue.  The Ideal would be to plumb with 1 1/2'  or larger so all pipe inside diameter sized flow is larger than the 1 1/4' actual pump output if you ask the pump manufacture.  as an example danner (supreme)  recommends 2" pipe on there 3/4 in output pumps to get there flow rates as advertised.    Real world what you have works and works fine.  There is a path to let excess away and not back up on the pump.  The way you had it, is like taking the car for a ride deciding that keeping your foot on the gas pedal to the floor, wide open, is to fast so you use the other foot to use the breaks to slow down fighting the engine thats wide open.  Somethings going to break and break bad before to long.

remember for flow rate versus velocity that larger diameter is slower and smaller diameter is faster with same flow rate.  it also takes more pressure to push the same flow through a smaller pipe.

This is a perpetual dilemma:  What should the goal temperature be? (rhetorical)

On the one hand, the nitrification bacteria love the warmer temperature.  As you note, they metabolize ammonia into nitrite then nitrate.  This process goes on faster with increasing temperatures.  While warmer temperatures mean less dissolved oxygen in the water (as I'll note below), this isn't an issue in a flood and drain system using an automatic bell siphon since the bacteria covered gravel bed is completely exposed to air many times during an hour since it cycles fast enough to do so.  So they have plenty of oxygen exposure almost regardless of how high the water temperature goes in your typical system.

On the other hand, higher temperatures mean (as you point out) lower dissolved oxygen in the water.  This stresses the fish and makes them more susceptible to infection, etc.  I really don't have to deal with this in the small system since goldfish and catfish are very tolerant of low oxygen levels.  So the temperature could do whatever it wanted to.

The Rainbow Trout in the large system look great.  They didn't want to eat this evening but they may still be stressed from the transfer yesterday afternoon.  They are swimming around the tank and they seemed 'playful', chasing after each other.  I dropped single pellets and some would mouth it and spit it back out.  I also dropped a couple of smaller earthworms but they didn't eat them.  The giant crayfish I have in there eventually made his way to the food and is eating it.  He looks great as well.  You can tell when an animal is moving around 'normally'.

So I feel pretty good about things so far.  The quarantine issue is a big one and I'm not sure there is really a solution for me.  I completely understand, though, that a bacterial or fungal or parasitic infection can wipe out the entire school of fish.  I think if I can keep the fish well-oxygenated and well-fed and watch the ammonia/nitrite then their natural immune system can do its work.

Great!  I didn't have time to fix it tonight but I will do so tomorrow afternoon.  I did buy the T junction and some pipe clamps today.  I just need a little more 1 1/4" tubing.

ETA:  The reason I went with the ball valve connect in-line, was that Tetra said to do it that way in their FAQ on their website:


They do mention the Y (or T junction) but they made it sound like it wouldn't matter which way you did it.

Quick update:  

1)  I've had a rough time with temperature.  It has been around 90F for the last couple of days with full sun.  The water temperature climbed to 76F today.  Ouch!.  The good news is that putting the well-fed garden hose in the sump tank for 30 minutes brought the temperature down to 72F.  I put it in for another 15 minutes and got it down to 70F which is where it is just now.  I'm still not sure what my goal temperature should be.  But 70 to 72 sounds like a good target.  I just checked and the temperature is supposed to rise to 95F tomorrow.  It's a large volume of water so it's difficult to warm up, but it's a large volume of water so it's difficult to cool down.  It's getting down to 65 tonight and tomorrow night.  

While I don't want to get OCD about the temperature, I have this weekend off so I don't see any reason why I shouldn't tweak the water temperature down to keep the water better oxygenated.  I don't want to kill the fish this early.  I'd like to wait at least a week or two for that!

2) I got the 1" PVC T junction and I glued about a 6" piece of 1" internal diameter PVC pipe to each of the 3 T parts.  I don't want to mess with it tonight any further because it's getting late so I'll get it connected to the pump in the morning.  I got an extra piece of 1 1/4" vinyl tubing since I'll likely need it when I cut out the ball valve.  I'll feel a lot better once the T section is in.  These pumps are not cheap and I also don't want to kill the fish if I can't replace the pump quickly enough.

3) The fish still aren't feeding aggressively.  I saw a couple of rises to some pellets I threw in but the temperature is so high that I'm not really surprised or too concerned about it.  They're still looking good though.  They're swimming around well.  I may salt again at 0.5 ppt.  I've lost quite a bit of water with the changes so adding 0.5 ppt will still keep me below 1 ppt.  They recommend a saltwater refractometer to measure salinity.  If someone can recommend one I'd be grateful.  I also posted in general discussion regarding a refractometer.

4) The 12 blue channel catfish are feeding well and look like they are growing.  They're much more active at night.  They are of course in the sump tank of the small system since they'd be attacked by the brown bullhead in the 55 gallon barrel.

I thought about taking the 2 smallest brown bullhead catfish from the small system and putting them in the large system to help keep it clean of uneaten food on the bottom.  I think between the brown bullhead and the crayfish, and the fact that the big tank drains any waste from the bottom of the tank, I can keep the large fish tank clean.  I know that ammonia spikes can be an issue with uneaten food.  I've only fed maybe one tablespoon total of pellets so far just to see if they're eating, so uneaten food should not be a problem.

5) I received the Jumpstart bacteria.  It's in the refrigerator right now.  You need to have some ammonia in the water for it to colonize well.  I'll check if there has been a bump in ammonia.  If so, I may add some of the bacteria.  This really is to supplement things.

That's all for tonight.

The temp fluxuations are worse then a steady higher temp in most fish. I dont know what the temp tolerance is for the rainbow trout but i believe they would be better off as a constant 78 then the up and down movement from you flushing sporadically.  The daily movement is a lot slower and easier on the fish then the "sudden" (30min)  drop. You will have variation in temo from am first light to end of the heat of the day.   I have seen wipeouts of systems with temp movement of 6* F daily due to the stress on the fish, then them getting sick and dying.  The temp is not what killed the fish its just what got then sick then die of the disease.   A fan blowing over the waters surface will also help cool or maintain a lower temp in the water.  

Tetra told you what you needed to know and no more,  there not going to make things to complicated or difficult on themselves.
The bacteria will colonize the bed with no showing of NH3 on the tests as the bacteria there now using it, the innoculent  will bring in the reinforcements and finish colonizing the rest of the bed.  the fish are producing waste currently, albeit not much since there not eating but they are producing some and the bacteria will scavenge that from the water to feed on. the bacteria will develop a higher  consumption based on load and will adjust as the load increases and decreases when its fully established

LET the bacteria slowly warm up inside the house from refrig temp, then take it outside to adjust again,  its like a polar plunge on them if you just toss them in, but reversed in temps

PM sent on refractometer

First, thank you for the information.  I didn't get the PM and I checked to make sure my box is not full.  If you can, please send it again.

A few comments/ideas on your advice:

1) I'm going to calm down on obsessing on the water temperature.  It sounds like I'm doing far more harm than good.  A 6F temperature change may not seem much, but even I can notice that it's a big change with my hand.  So I can imagine how much more dramatic it is for the fish.  Even lesser drops such as 2 to 3 degrees in a short period of time can have a great effect on stressing the fish from what you are saying.

The top temperature from all my readings for Rainbow Trout is 80F.  I think the idea is that above that temperature it is difficult to keep good oxygenation in the water at the level that can sustain the Rainbows even with good water agitation.  

I haven't calculated the exact water flow, but the grow bed fills and drains many times an hour, at least the required 5 times that I need.  The volume of the grow bed is about 200 gallons and can accommodate 100 gallons of water between the gravel.  So it's exchanging at least 500 gallons of water an hour but likely more, which is what the minimum exchange rate should be.  So the water in the fish tank makes one complete exchange an hour at least.  Since the water coming in is well agitated and I have the extra pump agitating the water, I think I'm oxygenating the water maximally for the water temperature.  

One reason I think oxygenation is pretty decent and uniform is that the fish are swimming at all levels of the tank.  Some are near the surface, mid-level and bottom.  They seem to explore the tank and at least go up to and mouth food that sinks in the tank (except for the moths which they eat).  The previous batch of fish stayed near the top.  That was likely because the high nitrites were not allowing proper oxygenation though.

2) I haven't added the Jumpstart bacteria (I had already ordered this brand before your first post) yet and I will do as you say in terms of letting it reach room temperature and then letting it reach water temperature before adding it to the fish tank.  I may only need half of the bottle so I'll maybe save some and cool it again slowly.

3) I did as you advised on the pump issue and added the T junction.  I hear you about what I found on the Tetra advice.  More dead pumps = more new pumps people have to buy.  The flow rate is easily adjusted:





I'm using a string to keep the end of the T overflow above the water line to add more agitation to the water and therefore oxygen.  The 2" return pipe also agitates the water in the sump tank so that further oxygenates it so it doesn't become stagnant and oxygen-depleted.



4) On the feeding issue, they did take a handful of moths I collected last night from outdoor lighting.  They picked them off the surface.  These were small live moths.  I couldn't get them to eat small earthworms, whole or in pieces.  They will take them in their mouth and spit them out.  I'll talk about the pellet food below in my updates.  

I found an article that states the top of the temperature range for feeding is 64F.  Above this temperature feeding slows with rise in temperature.  It may be one of several explanations for why they aren't feeding as well as I'd like them to.


A few updates:

1) I have two fish at least that appear to be infected with the trematodal parasite Diplostomum spathaceum.  It travels through their body and infects the eye causing cataracts.  I noticed them on Friday.  This is a very common infection in trout in aquaculture.  I may cull those fish.  Looking at the life cycle below, it does not appear that the fish can infect other fish as the definitive host is fish-eating birds with the two intermediate hosts being snails and fish.  I have been doing my best to keep snails out of my system but there are crayfish which certainly can host many parasites.



This is a picture from the website above:



Picture of one of the two fish I have from two angles:





2) I am buying fresh pellets today.  Though the ones I have stored in my basement are in a cool dry place, they recommend storing for only 90 to 100 days and mine are beyond that.  They could be giving off a scent that makes them not want to eat it as much.  

3) I planted the last of the tomato plants in the grow bed and also some corn which I had thinned out from the soil garden.  This picture below is the big system but was just before the last additions.  I know it is planted pretty thick.



4) These are the tomatoes in the small system.  These tomato plants were no more than 6 to 8" when first planted!







More later.

Update for today:


1)  The heat has continued.  Today the fish tank reached 76F, the hottest it has ever gotten.  Except for the two listless-looking fish with the infected eyes, the rest of the fish look great, flitting around the tank.  I think the oxygenation is solid from what I can tell and at this point the only way I would intervene is if the temperature would hit 80F, and then I would just add a little well water to get it down slowly to below 80F.  The hose has a misting head when you rotate it.  I think it will be hard for the temperature to hit 80F, though.  We have a cool rain tonight and we are supposed to go down to the high 50'sF mid-week.  I think this may be the toughest part of the summer to keep the water cool.

2)  They got a special treat of grasshoppers since I went raspberry picking with the family and there was a field next to it full of the grasshoppers.  The trout would come to the top of the tank and violently take them from the surface.  They would often spit it out and then one or two other trout would grab it.  It looks like someone would in fact finally eat it.  I bought the new feed pellets but they really weren't very interested in them.  I'll try again in the morning.  These are fresh pellets.

3)  I got the additional nitrifying bacteria into both tanks, small and large system.

ETA:

4)  I also put another 0.5 ppt of salt in the sump tank.  I know I lost quite a bit of water from the changes so even though I already added 0.5 ppt, I'm sure I'm closer to 0.75 ppt than to 1 ppt.

5)  I'm having a hard time keeping crayfish in the fish tank.  The outlet is large and the flow rate is such that they go over easily into the grow bed.  Since I have the bucket in there they get caught in it, but it's a pain to have to keep putting them back in the big fish tank.  I was hoping they would stay in there and clean up the bottom of any uneaten food.  I'm sure a lot of that just goes over into the grow bed anyway but I liked the idea of the crayfish.  

6) I caught some golden shiners that are about 6" long.  I will wait to put them in the big tank but I really like the idea of having them in there.  They can maybe take the place of the crayfish in scavenging uneaten food as they are in the carp family and will feed at all water levels from the surface down to the bottom.

If anyone has any questions or suggestions, please let me know.

Thanks for the updates C4. Did you remove the two fishes with the parasites or are they still hanging out?

Still hanging out.  My understanding is that infected fish do not shed parasites.  They only infect birds when eaten.  But I do plan to take them out.  

They seemed to like the pellets a little more this morning.  I'll try to stick to an am and pm feeding schedule.  I have a bunch of insects I caught near the light and will try feeding them early evening.

Whew, I finally got caught up on this thread.  C-4, I just replied to your PM.

Now some thoughts.  This may not be practical for C-4, as he has a limited time period during the year where he can actually run his system, but I would recommend to others that can run a system year round to cycle it with cheap goldfish or with fishless cycling using another ammonia source.  Killing edible fish through trial and error learning will get expensive fast.  

C-4, a couple ideas for you.  One, since you seem to be using wild caught fish, consider converting your smaller system into a quarantine system that can be used to isolate new additions.  You could run the quarantine system at a higher salt concentration, say 3 or even 4 ppt depending on the species of fish you want to add.  This will help neutralize parasites to keep them out of your main system, and provide you a place to treat other fish that may become infected with ich or the like.  It would also allow you to keep salt concentrations in your main system low to non-existent, so you can grow salt sensitive crops like strawberries.  You could run salt tolerant plants in the quarantine system.  Another idea, geared toward your growing season, would be to operate a run to waste aquaponics, where you grow fish in a tank and regularly refresh the water, using the waste water on a soil garden.  Here is a You Tube video of a guy in Florida doing just that.  This might be better for you, because with your climate, you will never really be able to let your system mature, at least not without running indoors during the colder months.  The more mature a system gets, the more stable it is.  Alternatively, read up on Dave Donley's system threads over at Backyard Aquaponics to see how he deals with aquaponics in a cold weather environment.

Yeah, if I had the luxury of time, I would cycle the system with Ammonium Sulphate.  As the ammonia was metabolized by the bacteria, the system's pH would slowly come down.  As you point out, I have a very limited time to do so.  I started the small system in mid-May (5/11 to be exact) and like everyone points out, it takes a good 4 to 6 weeks for it to mature.  I feel that the small system is finally reaching some sort of balance, though I understand that it continues to mature for many more months.  If I had known how bad algae can get, I would have kept the fish tank covered right from the beginning.  

I thought of the waste water idea.  If it's set up automatically like his, it's very doable.  It would be a pretty big project for me and I have space limitations given that the set-up has to be under as much full sun as possible.  I do use the water in the small fish system which has strong nitrate levels to water plants using a watering can.  I set up two 15 gallon water containers that I will keep filled with water next to the small system's sump tank.  I can replenish the water supply after using some to water the soil garden but because it is sitting there it will warm up to the tank's temperature and no cold water shock as I would get from the garden hose which has cold well water.

I like the idea of using the small system as a quarantine.  

Ideally, I'd like to be able to buy 6" blue channel catfish and use those in my big system.  But there is no way to get that where I live.  I think the Rainbow Trout are a reasonable alternative, but also having another fish in the tank to scavenge food scraps doesn't hurt.  

I'm still having a difficult time getting the Rainbow to eat the pellets.  They really weren't interested in them tonight, even when I broke them up a bit.  They went nuts for the insects and finally seem to have taken a liking to fresh garden earthworms if I cut them into pieces.  I caught a bunch of moths, grasshoppers, etc that I will give them in the morning.  I think I'll just have to plug along until they eat the pellets.  I've pre-soaked them and tried them dry and they are finicky with both.  If anyone has some advice, please let me know.  I bought a fresh bag so it shouldn't be a freshness issue.

Be Carefull with cheap goldfish, they are usually feeder fish and not well cared for and are loaded with potential diseases and or parasites.
The Qt system has been advised and the small set up could be used as mentioned above, or just a temp holding bin for 2 or more weeks before introduction into the growout system.  Another large tub on its own that you set up as a temp or such.  
The diagnoses looks right on for the 2 sick ones.   I would remove them sooner then later due to them being stressed, and more susceptible to getting an illness that is transferable

What was the temp of the water where you bought the trout?  what were they feeding on there.  Im sure they were on some type of prepared diet, was it floating or sinking, brand etc.  I have seen fish refuse to eat product A and devour product B, they would almost starve themselves if you only had prod A,  and i mean not eat for days or week or more 10 days or so then only eat a tiny amount of prod A a still spit most of it out, and in the mean time fouling the system with uneaten food the whole time if its not removed.  
try adding the pellets (do yours float?) at the same time you add some of the insects as a way to get them to better associate them with food.  Basicly training them.  
Can you get the channel cats at a local pet store?

I forgot to mention, you could mitigate your temp issues by switching over to constant flood.  This will slow temperature fluctuations, speed up cycling time and possibly improve oxygenation, although with the flow shown in your pictures and the number of fish you have, I really doubt oxygenation is an issue.  What's the cycle time like on your pump?  I see you went with a siphon, so I'm assuming continuous pumping?  There is a great thread on BYAP, I can't remember if I already posted a link to it, that trials various pump and drain methods, with the pros and cons of each.

Believe it or not, I never asked.  I am planning on calling him tomorrow and asking about that as well as what he feeds them and if I can buy some of his food to attempt to get them used to my food like you suggest.



I'm going to do my best to train them.  It will be easier if I can get some of the food they were being fed at the hatchery.  



Yes.  I bought another dozen about 1 1/2 weeks ago.  They currently have "ich" and I moved them into a 20 gallon container from the small system's sump tank.  I'm salting the water to 3ppt and I've added Malachite Green.  They seem to be eating Goldfish Flakes.  Hopefully I can get them healthy again.  ETA:  It never seems to end!  If it's not one thing it's another!  But that's OK.  I enjoy the challenge.  ETA2:  I wish I had a supplier with 6" blue channel catfish.  I think that would be the ideal fish for my system.  Although if I could get the trout to eat the pellets reliably, I would be happy with them as well.

Yes, continuous pumping.  I communicated by IM with an experienced member on Backyardaquaponics and they recommended continuous flow with an automatic bell siphon.  I was actually looking at doing it on a timer but the automatic bell siphon seemed much simpler.  

I see the big plus of the automatic bell siphon method being that the rocks are briefly and completely exposed to air during each cycle.  AS a result, the nitrifying bacteria get good oxygenation to maximize conversion of ammonia to nitrite and nitrate.  I probably get 5+ cycles per hour though I have not actually sat there and measured the number of cycles.  I have next week off for vacation but I'm staying home and will have time to do this.  It does cycle pretty fast so I'm fairly certain I'm filtering the whole 500 gallon fish tank through the grow bed once an hour.  Now that I have the adjustable T junction coming from the pump, it's really not that difficult to adjust the flow rate if I did need an increased rate.  

I plan on checking ammonia, nitrite and nitrate tomorrow after work.  They haven't fed a lot so I'm not too concerned but it will be nice to have good numbers.  Since the system is salted, the fish should be protected to some extent from nitrite, but ideally I'd like to have low ammonia, low nitrite and low to medium nitrate.  The tomato plants seem to be doing OK.  

Some updates to questions, etc.

1) The fish hatchery keeps their fish at 59 to 60F!  They don't have much of a choice because that is what the well and springs that feed the hatchery come out of the ground at.  It's completely believable since my well is 52F.

My fish tank is at 74F.  This could explain a lot of things, including their lackluster feeding.  Speaking of feeding . . .

2) I also asked what specific brand of fish food they use.  It's from a company out of Oregon called Bio-Oregon.  The specific feed is Bio Trout.  I got the name/number of the east coast distributor and they're across the border in Maine.  It's near Portland and it's a little too far to drive just to get fish food.  If I hadn't had to get home early after work I would have asked the hatchery for a handful of the feed to try out.  The bags are only sold in a 44 pound size and it would cost $17 just in shipping.  That's actually not bad but no way I'd buy it unless I knew they would eat it.

Fortunately, Bio-Oregon gave me the name of a store that repacks the feed in smaller sizes called Ken's Fish.  I called them today and though it was before closing I still got their machine.  I left a message and will call them back tomorrow.  

If the trout can't get warmed up to this feed, I'm not sure what I'll do.  I caught a bunch of moths tonight and will feed them in the morning.  As I'm sure leoismydog would point out, a temperature difference of 15F is like taking a penguin from the Antarctic and putting it in the Amazon River.  I still can't get over the temperature difference, and apparently neither can the fish!  I really need to be more patient with them.  It's been one week that they are in this system but may take longer to acclimate to it.

3) I took one of the sick fish out but couldn't catch the other one today.  I'll get it tomorrow.  It's in the refrigerator but I'm not sure what I'll do with it.  I noticed it had just a possible hint of 'frosting' on it's side and with the ich that my blue channel catfish have (more about that below), I got concerned enough to add another 0.5 ppt of salt.  That would take me up to 1.5 ppt that I've added total, but it's less than that because some water changes occurred in between.  I ordered a salt meter.  I read about ich and the freshwater variety does not tolerate salt very well, certainly less so than the fish.  So hopefully it will help from a prophylactic standpoint.

4) The baby blue channel catfish developed ich.  It was bad.  They were in the sump tank of the small fish system.  I don't know what stressed them out, but they got a terrible case of ich and I moved them into a 20 gallon bucket.  I salted the water to 3 ppt and treated it with Malachite Green but I came home today to several dead and dying fish.  The total death toll out of 12 fish was 8.  So I'm left with 4 fish and they're looking a lot better.  I did another water change and treated again with Malachite Green.  I'm not sure this is going to work out.  I just can't seem to get into a rhythm with them.  

Some good news . . .

5) I measured the ammonia, nitrite and nitrate in both systems and the values were all ZERO!  When the blue channel cats got sick, I stopped feeding the small system.  I think the bacteria are super efficient at converting to nitrate.  The grow bed is basically full and with 3 tomato plants, 2 cucumber plants, a small pepper plant, Swiss Chard and horseradish, I think the nitrates are getting absorbed very efficiently.  I did also add quite a bit of water to the small system from the 15 gallon water barrels.  These had warmed to ambient temperature so no temperature shock.  

I'm very pleased with the fish in the small system.  They are in great shape.  They stuff themselves with pellets.  They have no signs of disease.  They all get along, the brown bullhead and the goldfish.  These are the ones that overwintered in my garage!    

6) I finally did get a 1/2" plastic screen put over the outflow in the large system.  That means that I can put some crayfish back into it as long as they are large enough not to fit through the screen.  I did find one of the small trout had committed suicide by swimming up and out into the grow bed.  So with that and the sick one out, I'm down to 10 trout, soon to be 9 when the other sick one gets taken out.  So now I don't have to worry about fish or crayfish getting through to the other side.  If it does get plugged with debris (unlikely), water can still flow out through the top of the T-junction.

Please feel free to post any advice or questions.

General updates:

1) I'm still treating the 4 surviving blue channel catfish and they had another water exchange and they are still at 3 ppt salt and also Malachite Green.  One still has quite a bit of spots, although much better than originally.  The three other ones look great.  

2) I reached Ken's Fish and I have a 5 pound bag of Bio-Trout for $15 + shipping on its way, maybe even by tomorrow since they're right across the border in MA.  It's a little steep, but well worth it if I can keep the trout in my system.  If not, it's not like it will go to waste as it will still be fed to the catfish, etc.

3) I took out the second infected trout so I have 9 Rainbow Trout left in the system.  The four 6" Golden Shiners that are also there look great as well.  I put the large crayfish back into the big system since the screen is there and it cannot get out now.

4) The temperature is at 72F and we're supposed to have some cooler nights over the next week.  In terms of using the grow bed to lower temperature, I understand that using a constant flood would lower the temperature since warming of the water would be less in such a system during the day.  It's incredibly simple to do since it involves removing the automatic bell siphon.  Voila!  I could remove the bell siphon first thing in the morning and then replace it at the end of the day.  The one issue I have with that is such systems tend to cause "channeling" of the water directly from where it comes in directly to the outflow.  From my readings, it means less intimate contact between the bacteria-covered rocks and the water.  I may get lower temperatures but then less efficient ammonia to nitrate conversion.  

5) My friend that gave me the 500 gallon fish tank and the 600 gallon sump tank is getting back tomorrow from Iceland.  He hasn't seen the system in many weeks so it will be neat to show him how far it has gotten.  Now that I think about it, he has probably not even seen the large system set up at all so it's been even longer since he's been over than I thought.

6) I have the next week off so I'm going to redouble my efforts in catching more brown bullhead catfish and shiners.  I need some kind of fish in the system and I don't want to get caught without anything to take the place of the trout if they can't make a go of it.  I could just cycle the system with ammonium sulfate, but it kind of defeats the purpose of an aquaponics system and I'm really not interested in doing hydroponics.  I'd rather have more plants in pots given the space limitations.

If you have any advice or questions, please post them.

Avoid the channeling by forcing the water to be drawn from the bottom of the grow bed.  Use a gravel guard with the holes near the bottom and the top higher than the top of your standpipe.  You end up with more water contact with the bacteria because there are never any drain periods.  Properly setup, there shouldn't be any oxygenation issues either because the water is constantly flowing (think of a stream, where trout flourish).

Good point.  It's kind of too late for that set-up now since the holes are up along the sides of the gravel guard and it would be a monumental task to remove it and replace with a new one with holes near the bottom only.  Something to think about for next year though.

General Updates:

1) I went fishing last night for brown bullhead and caught 5 of them between 5 and 6" long.  Not big ones by any means but perfect stocking size for the big fish tank.  I hooked one deeply and while I know the general rule is not to attempt hook removal, I was able to cut the tip of the hook and remove it.  He looks pretty good this morning and he was the largest being closer to 7".  We'll see if he survives.  I now realize my previous mistake:  I had to wait until it was pitch black outside before the fish started biting.  I'll likely go back again tonight.

2) I also caught about 40 crayfish.  About 25 were very decent in size.  

3) I got the exact same trout feed the hatchery uses from Ken's Fish on Friday.  They re-package it into smaller bags but it is the same feed.  The trout are at least mouthing it.  Some clear differences I noted between the two feeds:

a)  The new feed (which the trout were raised on) is NOT floating.  It's very dense and actually sinks quite fast.

b)  It  is much darker than the other feed, a chocolate brown whereas the first feed is a light beige.

c)  It's also smaller, especially since the first feed really absorbs water and 'puffs up'.  

d) ? different flavor.  No, I didn't taste it, but they do smell different and I know that taste can make a big difference as to whether they will accept feed.


I'm going to do some brainstorming today and see how I will proceed next.  If I can get enough of the brown bullhead, I may give the remaining trout to a friend to stock his pond.  Then I'll focus on continuing the brown bullhead fishing this week and use them and the crayfish as the ammonia producers in the large system.  

I checked the various levels today in the large and small systems.  I received a nice salinity measurement device but I have to look at it some more.  I'm not planning on adding salt in the next few days.

The fish tank volumes and results were as follows:


––––––––––––––––––––––––––––––––––––––55 gallon fish tank––––––––––––550 gallon fish tank

pH–––––––––––––––––––––––––––––––––––––––6.5–––––––––––––––––––––––––––8.0

NH₃–––––––––––––––––––––––––––––––-–––-.75mg/L–––––––––––––––-––––––––0

NO₂––––––––––––––––––––––––––––––––-––––0––––––––––––––––––-–––––––––0

NO₃––––––––––––––––––––––––––––––-––––––0––––––––––––––––––-–––––––––0


The 55 gallon fish tank has 5 new brown bullhead as of a couple of nights ago and I think they are the source of the additional ammonia.  With a low pH, a good portion of the NH₃  is in the form of NH₄+ which is less toxic.  It's still something that has to be watched closely but at this pH it is nothing I'd have to do anything about.  I had reduced their feedings because of the additional fish so it's good to see that everything is still in balance.  I'm really happy about the reduced pH.

In the 550 gallon tank, it's a little surprising the pH has not dropped any from the well water pH (8.0).  The tomatoes and corn seem to be growing well.  I went fishing again tonight for brown bullhead and caught only one.  I really would like to purge the tank of Rainbows, run it for a week without any fish and then introduce the bullhead.  We'll see.

Quick updates:

1) I gave all but one of the Rainbow Trout to a friend who has a pond.  This last one was the largest of the second batch.  The larger the trout, the higher the temperature range it can tolerate which is why I think it is doing better than the rest of the trout.  I will likely give him away as well to have a system with crayfish and catfish only.  I think I gave the trout a fair shot.  After doing more reading, I simply have a temperature range that is too high for trout species, although there may also be other factors in play here.

2) I have 5 brown bullhead catfish in the large 500 gallon fish tank that are the ones I've had the longest.  I have another 8 in the small system that I am waiting to put into the larger system.  I am using the small system as a 'holding tank' to make sure the fish survive the 'getting hooked' experience.  I'm using barbless hooks but some of them get hooked good.  

I have had a blast exploring the area looking for other places to fish for the catfish.  If I plan on growing these out to 1 pound, and the large system's grow bed can sustain 48 pounds worth of fish, and I play it safe by using 50% of that, then I should be able to start off with 24 fish.  So I need to keep fishing and get another 11 fish.  I do have the crayfish as well, but I do not think they are big ammonia producers.

3) The water is cloudy again!  Not like the original pea soup algae bloom I had with both systems, but I had had very clear water for a long time.  It was crystal clear to the point that at night I could use a flashlight to see down to the bottom of both systems and observe the fish, or during the day I could see well in full sun.  

We did get a bunch of rain for about a week and a drop in temperature.  I think this combined with moving fish around likely led to some disturbance in the water chemistry making algae grow better.  I'm a little surprised in the small system since I cover the fish tank during the day and only a little light gets to the water in the small system through the sump tank.  The large system probably gets more sunlight because the 500 gallon fish tank has a camouflage netting over it but a good amount of sunlight still gets through.  I am going to cover the fish tank with a tarp during the daytime in case this is an algae issue.  From my readings, algae is killed pretty effectively if it gets no sunlight for several days.  Another thing that may be playing a role is that the new food may be contributing to this chemical imbalance so I'm going back to the original brand of food since that did not cause any cloudiness and the catfish will eat either food.

I had also bought some more Barley Extract and had not treated the water with this for a while.  They recommend regular use (of course because they want to sell more!) but I also think that it does in fact have a powerful inhibitory effect on algae, assuming that is what is causing the clouding.  There may be different reason(s) for clouding.  


There are other more minor issues I'm dealing with.  I found a sore on one of the catfish I've had forever.  Not sure if it got injured by one of the giant crayfish or what.  I have to admit that this has been a huge challenge so far, especially the large system.  Two steps forward, two steps back.

appreciate the updates

Are there any fish species that eat alge? Maybe put a couple of those in there for control?

No problem.



I know Silver Carp are strict filter feeders but I'm sure they are regulated in terms of importing them into the state.  If I had a few small ones it would likely take care of any algae issues.  Most other algae feeders take the algae off a substrate, but mine (if that's what it is) is suspended in the water.  I will look into ordering some.  It's surprising what you can get through pet stores.

Quick Updates:

1) Because I couldn't see easily to the bottom because of the cloudiness, I shut off the pump and siphoned water from the fish tank directly into the sump tank.  This allowed the fish tank water level to drop by about 1/3 so I could see much better.  Since no water was actually removed from the system, this shouldn't have any significant effect on the water chemistry.  

I was greeted to a cannibal holocaust among the crayfish.  Body parts were strewn across the bottom of the tank.  I think this may have disrupted things a bit.  I've known since being a kid that crayfish will fight to the death but I've seen it first-hand again.  I'm starting to think that maybe the high density of crayfish was a bad idea, although a self-correcting one.

2) I found 2 remaining Rainbow Trout, not 1.  I gave them away so now I am officially trout-free.

3) The 5 brown bullhead catfish looked great.  I did remove the one with the cut/sore on its rear lower jaw area, and after inspecting it, my sense is that it may have tangled with one of the larger crayfish.  It didn't look any worse for wear but I'm going to observe it in the sump tank of the small system for a couple of days.

4) I've kind of given up on guarding against cross-contamination.  I think next year if I keep up with these systems I will make a strong concerted effort to keep the small system for quarantine before transfer to the larger system.

5) I will get some pictures up of the of the tomatoes and English cucumbers.  The latter are growing very nicely and I have two cukes that will likely be ready to harvest soon.  I have two cherry tomatoes that are starting to turn red.  The Habanero pepper plant in the small system has small peppers on it though the plant has remained much smaller than its potted counterparts.  

ETA:

6) I removed the smaller pump that was pumping water from the bottom of the 500 gallon fish tank to the top, thus creating more oxygenation and agitation of the water.  Without trout species, it's just not necessary and simplifies the set-up.  

7) I also removed the netting since catfish don't jump, but I may put it back to keep leaves and such out of the system.  I have noticed a leaf or other piece of debris on top of the net almost on a daily basis so it actually may be useful to have it there to keep the outflow from getting plugged.

All in all, I'm feeling better about the two systems.  If the water starts to clear up and I can get the requisite number of brown bullhead into the big system I will likely be able to cruise into the fall barring some disaster.

After reading this thread I realized I don't have the time, energy or interest growing my own captive fish in a closed-loop system

Helluva good thread though.  It taught me quite a bit.

TRG

Thank you, TRH.

With the stream you have, you could make a killer pond some day.  You could have the stream come into the pond and an overflow pipe to drain it so fish would stay inside.  I'm not sure what kind of permits you would need, but it would be doable.  Then the only thing you'd need to do is stock it with some blue channel catfish and feed them once a day.  The flow through system would take care of the fish waste.  Like you point out, the closed-loop system requires a lot of management.

No permits needed.  I had the US soil and conservation department come and do a casual survey once.  The soil type in my area is conducive to making a pond, but, it would require too much money to make it worth my time.  I have alot of big trees and deep sand to move and that investment is low on my priority list.  

There are 2" to 6" bass and perch in my creek already.  If I needed to eat them, they aren't hard to catch.

TRG

Been looking into aquaponics for quite awhile now and loving your updates so far. But something just occurred to me: shouldn't I be able to cheat by simply running water straight from my stocked pond through my garden? Granted the pond slowly loses water but I wonder if it wouldn't be the same basic concept, all while not having to worry about ph levels etc.

Yes, but . . .

If you mean a soil garden, then I would imagine that there would be issues of washing soil into the pond.  If you have a garden in artificial media like gravel, then there is no reason why it wouldn't work.  You still need to be able to pump the entire volume of the pond (ETA) every hour through the gravel in which you have plants growing.  That's basically the minimum recommended.

What is the size of the pond and what kind of fish do you have?

My tomatoes and English cucumbers are ready to harvest.  The small system actually has quite a bit more, but it was started earlier.  I thought I would use indeterminate tomato plants on the edges of the big system and let them hang over, but because of several reasons they haven't done as well as I would have hoped by now ie. started late, the system hasn't matured fast enough, determinate cherry tomatoes seem to do best but there is a mix of both in the big system, etc.

Small system first:

This is the Swiss Chard.  A lot of the sunlight was blocked by the larger tomato plants so they didn't do well at all.  Last summer in the garden, the plants got tall and strong.



The 2 English cucumber plants got huge.  The plants were robust.  I let them grow out of the 20 gallon grow bed to give them more room to grow and capture more sunlight.  One plant has 2 mature cucumbers and the second one has 1.  We've eaten them and they taste no different than ones from the soil garden.







This is the one Habanero Pepper plant I have in the aquaponics system.  It is a tiny plant compared to the potted ones, but that is understandable since it was planted later than the tomatoes and is not getting a lot of sunlight.  The peppers look like they're big enough that they should mature no problem.





The small system had 2 Husky Cherry Tomatoes indeterminate hybrid.  They've grown amazingly well.  The first picture below is from when they first went in.  The tomato plants were maybe 8" tall.  The second is a view from the top now.  There's a lone Red Indian Corn plant between the tomato plants and some horseradish as well.  The rest are pictures of the cherry tomatoes.  They taste no different than Cherry Tomatoes I've grown in the past.





Ripe:






This one is a third tomato plant that already had a small green tomato on it when it went into the system.  It doesn't get a lot of sunlight so it hasn't grown much.  Also, the plant has put a lot of energy/growth into this nice red tomato:



Big System

The corn and tomatoes were put in here later so they haven't grown as well.  There are some cherry tomatoes and one larger variety.  One cucumber grew well which is the second picture.  The first one is just an overall view of the large system.  The goal really given that I started late was to have good growth to absorb as much nitrate as possible.  So I'm not disappointed in the harvest.  Also, if I do this next year I will try to use tomatoes only in the systems.  The 3rd and 4th pictures are cherry tomatoes.








Before and after of the large system.  The second picture is obviously a large view of the entire mess of the two systems plus my potted pepper plants, banana plants and butternut squash growing everywhere, including up some netting I put on the railing.    





Butternut squash between potted pepper plants.  I will likely have about 10 of these, maybe more.



I had a great time fishing tonight which is why I am posting this so late.  I will post pictures of the brown bullhead catfish I caught tomorrow.

Butternut Squash with Walnuts and Vanilla

You will thank me later....

Thank you!  I'm always looking for good recipes, especially for squash.  This is only the second year growing them (ETA: Butternut squash specifically).  It also helps that I love vanilla and walnuts.

Someone brought up the point of licensing with me the other day and I wanted to mention it here briefly before going on with the updates.  I will put this in the original post just to make sure no one gets themselves into trouble with Fish and Game.  

Laws vary from state to state, but, generally, a license is needed to engage in aquaculture if you are using wild fish as stock, or if you are using a system that is or can possibly become connected to a waterway.  As you all know, non-native species being released into the wild is a problem throughout the U.S. and they can destroy local fisheries.  Even species that are native to a state but not specifically to a particular pond, lake or river can pose a problem if released there.  In New Hampshire (and I suspect in most/all states), Fish and Game does not allow the transportation of live fish by fisherman unless it is on a specified bait species list.  There are exceptions including those with an aquaculture license.  In NH, a non-commercial aquaculture license allowing you to catch and transport wild fish for stocking your aquaponics system costs $20 a year.  This is in addition to a freshwater fishing license.  Since I've been using wild-caught hornpout/brown bullhead catfish, I have had a non-commercial license.  My point is:  Check the laws specifically in your state to make sure you don't run afoul of any of them.

A few updates:

1) The cherry tomatoes in the small and large system are going crazy.  I'm very pleased with them and it looks like I'll push mostly tomatoes next year if I do this again.

2) The large system is looking great.  I removed the camouflage netting and I have a blue tarp in its place.  It is connected to my deck at one end and drapes over the 500 gallon fish tank.  It looks more neat and blocks out a lot of light.  I think this is the reason the tank's water has cleared up nicely to the point that I can see the brown bullhead catfish easily on the bottom with a flashlight or with sunlight during the day if I move the tarp over.

3) I am now up to 25 brown bullhead catfish in the 500 gallon system.  They look great.  They feed very well on the pellets.  I use the same trout feed pellet that I soak for about 10 minutes so it sinks to the bottom.  The fish feed aggressively.  I even spotted the remnants of a large crayfish that I suspect was torn apart by the catfish.  I am going to have to increase the amount of feed.  

4) With the catfish, I feel a lot more relaxed about the system.  They do not have the temperature requirements that the trout had and they can adapt to many more conditions.  Brown bullhead tend to prefer non-moving water but they don't seem to mind the current in there right now.  I don't know how big they will get but my system can handle them easily even if they were to get to a pound each.  I think the time I have left before shutting down the system will make it unlikely that they will get near that.  

5) My wife is getting sick of listening to me talk about aquaponics.

I did promise pictures of the fish and didn't deliver.  I'm planning on catching 5 more catfish as my goal is 30 fish in the system, and I'll post pictures of them.  I have had a chance to explore more ponds and that in itself has been very pleasurable.

You're going to shut the system down?

I went over this a little earlier in the thread.  The nitrifying bacteria in the gravel grow bed are responsible for converting ammonia to nitrite and then to nitrate.  For every 10 degree F drop in temperature, the bacteria's efficiency in converting of ammonia to nitrate drops by 50%.

It is also true that as the temperature drops, the metabolism of the fish goes down.  However, the bacterial conversion efficiency drops faster than the fish's ability to produce ammonia waste drops.  Eventually the temperature drops to a point where ammonia will build up in sufficient quantities to reach lethal concentrations and kill the fish.  

If I had an indoor/greenhouse system, I could keep the temperature high enough for the bacteria to remain active.  Since I do not, I am completely at the whim of outdoor temperatures.  I thought about just running the system as is but without feeding the fish, but the problem with that is the temperatures get well below freezing and I am sure I'd have lots of problems with ice in the tubing and elsewhere in the system.  Also, snow will be a big issue.

I spoke with Debbie Gile president of The New Hampshire Aquaculture Association for the first time recently.  She has a large greenhouse aquaponics system that she is setting up and plans to run through the winter.  I brought up my plan for the system I have and she agreed that bringing the fish into my unheated garage is likely the best solution.  

This is my likely plan though that could change:

1)  I plan to bring the 100 gallon Rubbermaid stock tank from my small system along with all the fish into the garage once the temperatures get near freezing.  I will stop feeding the fish long before this, probably when the water temperature drops consistently to 50 degrees F as that is when Koi and goldfish pond owners usually stop feeding their fish.

2)  I will place about 6 to 8" of gravel from my large system into the bottom of the 100 gallon stock tank.  

3)  I will have an aeration bar under the gravel to help circulate the water.  I may have to add an additional small pump just to keep the water circulation to help keep it from freezing.  The garage is unheated, but it is connected to the house so it's always quite a bit warmer than outside.

4)  The fish will not be fed.  They will still have a tiny amount of ammonia production through normal respiration even though they will essentially be in a 'hybernating' state.  The bacteria will remain alive and should be able to handle this tiny amount of ammonia.  In any case, I do plan to do some water changes, maybe 5 gallons a day or every other day.  

5)  I do have some experience with the above as I kept a 20 gallon plastic container with goldfish and 3 catfish in my garage this past winter.  They were not fed and were the first ones into my system this year.  In fact, they looked no worse for wear.  I did have problems keeping the water from freezing over and had to chip away at some ice on the surface during a two week period in the dead of winter.  (ETA:  I did have a bubbler but that was not enough to keep the water from freezing on the surface almost completely.)  This time around, I may get a stock tank heater to keep the water temperature from freezing, but I don't want the temperature to get much above the 30's since I don't want to increase the fishes' metabolism.  I think with the bubbler and and a small pump circulating the water should be more than enough though.

That's the plan for now!  However, it will be a while before I have to shut things down.

ETA:  The reason for bringing a quantity of gravel into the garage is to keep it > 32 F so that I can use it to 're-stock' the bacteria in the rest of the system come spring.  It also should take care of any ammonia from the fish who will be at a low metabolic rate, but I'm going to do water changes as well.

Have you given any thought to adding an LED grow light and growing a few heads of lettuce or cool weather crop while the fish are hibernating in the garage?

Good question.  I did think about this.  The garage is just way too cold in the winter, so that's out even for a cool weather crop.  I thought about just bringing the small system indoors altogether into the basement.  The problem I would run into is the fish, especially if I had 25 to 30 of them, would quickly outstrip the bacteria's ability to detoxify the ammonia.  If I kept the feedings at a level that would not create toxic ammonia levels, I would essentially be starving the fish.  Plus, it would be a great undertaking to bring everything inside and even if my wife were on board with it, I don't think that I would be.  I really enjoy this project, and if I were living in a place like AZ that would allow me to do it year-round then I would do so.  But that's not the case so I'm going to run it as long as I can into the fall and then let the fish 'hibernate' in the garage.  That will still require some work/maintenance and should make for interesting if few posts.  

Another option is to bring gravel into the garage but eat all the fish.  I think with all the new fishing spots and techniques I've learned over the summer to catch the catfish I could re-stock it in the spring quickly.  But I'm going to plan on keeping the fish.  It's simpler that way and I can hit the ground running faster in the spring.  Hopefully I can get them through the winter.  

I can't say my plan is the most correct thing to do because I've never done it before beyond the small experiment last winter.  But I feel confident about it since I discussed it with Debbie Gile and she is very knowledgeable about the subject.  There have been a few posts here as well about it.  So there is some logic behind what I'm doing.

These are a few pictures from the last time I caught some fish.  I put them in the small system as a pseudo-quarantine, mainly to make sure that if any fish died, they would be easier to deal with in the small system.  Since the small system is, IMO, fully matured, I think it would deal with a dead fish and the resultant ammonia spike better than the large system.  I didn't expect any of the fish to die and none did.  

One thing I noticed, is that when I put more fish into the small system, there is a mini algae bloom.  I think the additional ammonia disrupts the normal balance.  Since moving all the catfish into the large system, the water in the small system has cleared up again.  

Fish in the bucket fresh from the pond:



This one lost its left eye to the hook.  It was a barbless hook but it hit it just right.  It survived so I'm not worried.



More fish:







Next post I'll address feeding.

There is some good information out there regarding the amount of feed requirements based on fish size and water temperature.  The smaller the fish, the larger amount of food they need as a % body weight.  As temperature rises, they also use greater amounts of feed but beyond a certain temperature feed requirements actually fall.  The following article is what I used mostly in determining how much feed to use:  Review of Feeding Practices for Channel Catfish Production

One of my problems is that I do not know the exact total weight of the fish I have.  I weighed one of the larger ones and it was 6 ounces and was a little under 8".  This comes out to 0.375 pounds which is about right according to the .pdf table here.  

If I use an average of 0.2 pounds per fish and multiply by 26 fish, I get 5.2 pounds.  Divide by 2.2 pounds per Kg, I get 2.363 Kg of catfish.  

The feed rate according to water temperature is as follows:


It gets a little complicated because as the table above notes the amount of feed as a % body weight changes as the fish grows, with the fish needing a smaller %.  So you have to feed according to both fish size and water temperature.
  There is another table in the link that adjusts feeding per % body weight depending on the size of the catfish.

Taking my water temperature range (60 to 70F) and the fish size into consideration, I should probably feeding 3% body weight per day.  

This would come out to 3% of 2.363 Kg = 0.07089 Kg = 70.89 grams = 71 g of food per day total or 35.5 g twice daily.

I've been more conservative and used 2% as a value since I may be overestimating the weight and I have a closed system, not a pond, so I do have to contend with nitrogen waste having to be processed.  So I would rather underestimate the amount of feed than overestimate it.  I do get some uneaten food that comes over into the gravel bed but it is a tiny amount compared to how much I am feeding so it's unlikely that they are being overfed.  I also have good water clarity so I can inspect the bottom of the tank at night with a flashlight to make sure there isn't any uneaten food left from the previous feeding.  I had opted not to put gravel on the bottom of the tank mainly because I wanted to be able to inspect for uneaten food and also to make it easier to see any dead fish.

Since I'm using 2% of body weight of food per day, it comes out to 47.26 g.  I have a little scooper that when filled level with the top will hold 11 g of food.  So I have been giving 2 scoops or 22 g of food twice a day for a total of 44 g of food daily.

Quick updates:

1) I saw a couple of fish "flashing" in the big tank which is when they turn on their side and rub against the bottom or side of the tank.  There can be several reasons for this including parasites or high toxin levels (ammonia, nitrite, nitrate).  It's not necessarily an indication that there is something wrong, but it is important to keep track of their behavior and use it as an opportunity to double check everything.  If you watch wild fish, you can often see them flashing.  So I checked the levels of ammonia, etc.

The fish tank volumes and results were as follows:


––––––––––––––––––––––––––––––––––––––55 gallon fish tank––––––––––––550 gallon fish tank

pH–––––––––––––––––––––––––––––––––––––––6.5–––––––––––––––––––––––––––7.0

NH₃–––––––––––––––––––––––––––––––-––––––0––––––––––––-–––––-––––––––––––0

NO₂––––––––––––––––––––––––––––––––-––––0––––––––––––––––––-–––––––––––––0

I did not check nitrate.

So I am not worried about the flashing.  I did notice tiny filamentous worms in the water.  There are so many things that can grow in the water that are benign that I'm not concerned.  The fish are swimming around and generally looking extremely healthy.  Brown Bullhead catfish can live in fresh or brackish water but I'm going to hold off on putting any salt in since they look so good.  Salt will mitigate nitrite toxicity but no need for that at this point.  No deaths at all and I did see what I thought was part of a hook.  One of the fish did still have a hook inside it so I imagine that was it.  It just shows how hardy these fish can be.

2) The pH has dropped dramatically in the large tank in the month since I last checked it.  That's really good news since it tells me the system is maturing.  Just in time for winter.

3) The water temperature has been hovering around 62F.  It's ironic that I did everything I could to keep the temperature low with the trout and now I would love to have temperatures in the 70's!  I'm done with trout though.  

4) They are feeding very well.  Several of the catfish were filled to the brim with food last night so I held their morning feeding today.  I just checked them and their stomachs have gone down so I'm putting them back on their regular feeding schedule.  I don't want any extra food collecting in the tank.

5) The tomatoes are still growing very well and also ripening nicely.

ETA:  I just fed the fish.  I like turning off the pumps and letting the water come to a standstill.  I let the food soak in water separately for about 10 minutes.  By then the water is still.  I then drop the food into the water and watch it sink with a flashlight.  It's fun to watch the catfish go into a feeding frenzy literally vacuuming up all the food.  I also do drop the dry pellets which eventually sink to the bottom but it's more fun to watch them gorge themselves.  Maybe it seems so amazing because the trout fed so poorly by comparison.  It's very relaxing and satisfying to watch fish feeding, or any animal for that matter.

A quick update:

1)  I saw a fish flashing (once) so I did check the nitrate level today at lunch in the 550 gallon tank and it came back 25mg/L.  That's fine.  For all you aquarium enthusiasts, it's not a bad level.  Combining this with the 0mg/L ammonia and 0mg/L nitrite information from the other day tells me that the bacteria are still functioning well.  The temperature has been dropping unfortunately.  Today it was around 60F.  I really wish I had warmer water for them.  I can't believe I'm having the opposite problem with temperature.  I wish I had started with the catfish but hindsight is 20/20.

We are supposed to have warm daytime temperatures over the next few days but I still think this is entering dangerous territory.  I can foresee a significant drop in bacterial activity as the temperature trend drops.  I am going to have to keep a good track of temperature and alter the feedings accordingly.  I don't want the ammonia or nitrite levels to spike and kill everything.  I will measure the salinity and likely add some salt to help protect against nitrite poisoning.  The chloride ion displaces nitrite ions in the fish's blood thereby reducing fish nitrite levels.  Nitrite oxidizes hemoglobin and thereby renders it useless for carrying oxygen which therefore leads to suffocation of the fish.  

The other thing the nitrate levels tell me is that the plants are not starved of nitrate.  I will have to plant more tomatoes next year and get stakes put in early so that I can keep the tomatoes growing straight up.  I will also have to plant the tomatoes as early as possible to get as much growth out of them as possible as I did in the small system.  I need to take advantage of the nitrate sucking properties of tomatoes to keep the nitrate levels as low as possible especially since the fish (hopefully) will grow larger and I will need more nitrate absorbing capacity from my plants.  Adding another grow bed is simply not possibly because logistically the space is not there.  I have blueberry bushes to the left of the system when looking at it from the deck.  

I will also have a couple of 100 gallon water water barrels set up in such a way that I can fill them and let them warm up to ambient temperature so that I can do water exchanges to keep nitrate or other toxin levels down without causing temperature shock to the fish.  This will be more for when I start up the system hopefully in the spring but also later in the season if nitrate levels become a problem as the fish grow.

2) Here are some pictures of the fish in the tank.  I took them during the day by partially uncovering the tank to let sunlight in.  I apologize for the poor quality but I'm not a photographer so bear with me.  Also, I couldn't pick which ones to post so I posted most of the ones I took:

You can use the 2" internal diameter PVC pipe in the following pictures to orient yourself.  The bottom of the tank can easily be seen and it's important so I can monitor any residual food.













You can see the edge of the fish tank here:





The following pictures were actually taken a couple of days ago IIRC.  The quality is even worse but I like the eery perspective it gives.  If you look at the bottom of the drain tube, you can see two lighter objects on it.  Those are crayfish.  There are probably only 8 or 9 left.















That's it for tonight.

thanks for the update C4