So I got my new safe and it's in my detached shop as it's too big to go in house where old safe this one replaced.  Inside the shop I have another small room so I put the safe in there.  Inside the safe I have one small Eva-Dry and one large Eva-Dry rechargeable desicant packs.  I also have the large 36" golden rod inside the safe and the hydrometer says 60% for a week now.  I can't seem to get it under the 60% and when I had another safe inside it was always around 40%.  I have all AR's in the safe and polymer handguns.  I've  wiped them all down with Rig so I haven't had any rusting problems yet.

Is 60% too high? I live in Iowa, the heart of the midwest and humidity is a problem in the summer.  I have the small room all sealed off so I was thinking of adding a larger dehumidifier in the room to remove what humidity is in there.  I have a bit of OCD so I just want to make sure I'm not going to ruin my guns.  I only open this thing maybe once a week or less too if that matters.

Thoughts?

Try a different hydrometer, or chech the door seal. 60% is damn close to the ambient humidity, and with all that stuff running, you're not getting any decrease.

I had thought about doing this, I will have to order another one and give that a try.  I think the seal is good but I will take a look there too.

Are you getting a temperature delta between the inside of the safe and the room?
I personally prefer to keep the safe about 10 - 15 degrees warmer than the room.  I doubt a Goldenrod has enough wattage to do this.  

Lots of guys use rods on here and like them.  I just prefer something a little more.

Try a different Hygrometer.  I lived in Missouri with Garage Safe for years with no issues.

Maybe try this,

750

Bulk cat litter, the silica crystals kind can be used in your room.  Also, consider a portable dehumidifier which will make a huge difference,

http://www.sears.com/appliances-air-purifiers-dehumidifiers/s-1023564

I put a large, think it's 50 pint, portable dehumidifier in the room.  Safe is down to 45% now, temperature in room is up, and swapped out the hydrometer.

60% isn't horrible.  Don't go below 40%.

Mine often runs around 60%, but it is always 8-10% lower than outside (in a non climate controlled garage type building).  I think wihtout knowing your outside humidity, the absolute number isn't that critical.  Open the door, read humidity (and temp) then take hygrometer out and read outside humidity in a few minutes.  That will tell you what your dessicants are doing.

I'll bet your indoor humidity is closer to your original 40% assuming you have air conditioning.

You can calibrate your hygrometer also, do a Bing search (don't use Google as they are a bunch of left wing Obama supporters).  Take a small container (even a soda bottle cap) fill with salt and then put in enough water to get salt wet (but no standing water).  Seal that in a Ziplock bag with your hygrometer.  The salt should stabilize at 75% humidity (may take several hours, I'd leave it overnight).  That way you can at least see how far off your hygrometer is to a real reading (ie. if it reads 72% you know that your actual humidity should be about 3% higher than indicated).

If you have it in a walled off room and run a dehumidifier, I'd recommend that.  That's what I plan to do (going to build a room for a dehumidifier just to store thnigs like elecronics, papers etc).

The key to preventing condensation is maintaining a delta-T from outside to inside. The larger the margin, the better. A few degrees is adequate if the environment does not have big swings in ambient temperature. The wider the ambient swings, the greater the temperature differential should be. The humidity is not the issue, and there is nothing wrong with 60% relative humidity. The problems come when the internal temperature reaches the dew point. It's right to be more concerned with a good delta-T when higher humidity is present, because the dew point is closer to the ambient temperature. Just make sure your internal temperature remains above the outside temperature at all times and you are golden...

Ditto.  Right on.
Gun metal will feel noticeably warmer than ambient once removed from the safe.  The moisture in the air film surrounding the metal cannot condense.

OK, I am confused about a couple things, I hope you can clarify.  If you have a safe that is heavily "insulated", think TL-30X6, it has no hole for a golden rod or similar and I am actively using desiccant in the safe.  In a garage environment, the garage temperature would (seems to me) be above the safe temperature just based on the facts at hand. Safe (dark, cool, insulated), Garage exposed to sunlight, windows, etc).  Maybe I am not understanding something.

My non-calibrated hygrometer (cheapie Lowes digital) showed internal safe at 48% humidity at 73 degrees when I spot checked it yesterday.

A safe, or any other object, no matter how big or how dense, will exchange energy with the environment until the whole reaches equilibrium. The X6 does not have a perfect seal, nor does any other conventional safe, even if they have resilient compressed seals. Making a perfect seal is virtually impossible in a big steel box. Ask me how I know

Unless there is an active influence changing this system, there will be and equilibrium point. A GoldenRod disrupts the process, because it constantly adds energy inside the safe at a higher rate than the heat escaping until a constant energy flow is established thru the walls you stabilize at a constant delta T from the inside to the outside. If you put in more power (heat energy) you get a larger delta T.

So, the thing that we can't control are the swings in the temperature of the environment. If the swings are rapid and significant, then equilibrium won't happen. The problem comes when the safe, and the contents, are cool, and the temperature rises rapidly while there is high humidity. That's when the temperature of the metal parts of the gun can be cool enough to reach the dew-point as the air temperature rises. That results in the dreaded condensation of destruction.

Again, it's not the humidity that you need to worry about, it's the dew-point. So, if your environment is stable, you can get away with minimal measures. If your temperatures swing a lot, use more drying or heating measures.

Thank you!  The extra information helped me understand.

I'm in the low 30s all the time.  Why not go below 40?  The drier the better.
OP says he has all ARs and polymer handguns.  He has no wooden stocks to dry out.