As posted in the survival forum
"From EPA website
"You can use granular calcium hypochlorite to disinfect water.
Add and dissolve one heaping teaspoon of high-test granular calcium hypochlorite (approximately z ounce) for each two gallons of water, or 5 milliliters (approximately 7 grams) per 7.5 liters of water.
The mixture will produce a stock chlorine solution of approximately 500 milligrams per liter, since the calcium hypochlorite has available chlorine equal to 70 percent of its weight.
To disinfect water, add the chlorine solution in the ratio of one part of chlorine solution to each 100 parts of water to be treated. This is roughly equal to adding 1 pint (16 ounces) of stock chlorine to each 12.5 gallons of water or (approximately ? liter to 50 liters of water) to be disinfected.
To remove any objectionable chlorine odor, aerate the disinfected water by pouring it back and forth from one clean container to another."
I have read that "high-test calcium hypochlorite" means 78%.
I figured that out of the big three (food/water/shelter) this was the one thing that would probably do the most good for the SF community.
REMEMBER - when using liquid bleach to purify water, the formulas all are counting on bleach to be about 5-7% strength...which after 6 months of shelf storage is no longer a sure thing with liquid bleach. Storing liquid bleach long term isn't effective, as it will loose its effectiveness after 3-6 months link
Storing granular calcium hypochlorite (pool shock) is cheap and easy and the shelf life is much longer.
30 bucks of the right sort of pool shock would probably purify a lifetimes worth of drinking water for several people in ideal conditions. I first read about this on SF and didn't figure this out all on my own but I did do the research with help from SF and refined things to this point:
Here is what I found: http://www.epa.gov/safewater/faq/emerg.html
Pay attention to the section on granular calcium hypochlorite to disinfect water. Read the whole thing as it paints a big picture to understand but I really liked the idea of being able to treat a lot of water, for just a couple bucks.
Granular calcium hypochlorite is available from Leslie's pool supply in 73% strength with a minimum average yield of 70% chlorine - perfect for what we need. (see pic for example of product) Its sold as common everyday Pool Shock.
Read the label of the pool shock closely! All you want to use for this is high concentration of Granular Calcium Hypochlorite and nothing else. Be careful to avoid the multi-function pool shocks that have chemicals like algicides and other 'multi function 4-in-1' products. All you want is Calcium Hypochlorite at 65% or stronger. Don't worry about the ingredients listed as 'other' those are the inert parts to keep the concentrations down to where they want them. So long as no other chemical is specifically listed then its OK.
Materials needed (maybe 10 bucks worth of stuff):
1 bag of Leslie's 73% Calcium Hypochlorite Pool Shock ($4)
a couple 5 gallon buckets ($0 - $5 depending on how you get them)
a funnel ($1)
a couple empty bleach containers ($0 save them as you use them normally)
Step 1: Make bleach
1 heaping teaspoon of pool shock makes 2 gallons of bleach
- place 2 gallons of water into a 5 gallon bucket
- place 1 heaping *teaspoon* of pool shock into bucket
- stir into solution thoroughly
- place funnel into empty 1 gallon bleach container
- pour 1 gallon out of bucket into bleach container
- repeat for other bleach container
Now you have made two gallons of normal household bleach that you can use for anything you would normally use bleach for like cleaning, disinfecting etc.
Step 2: Use bleach to disinfect water
- 2.5 *tablespoons* of bleach solution goes into 1 gallon of water for disinfecting
- stir into solution and wait 30 mins
- sample taste the disinfected water, if it tastes too strong of chlorine then aerate the water by simply pouring 1 gallon from one container into another a couple times and this will help remove the objectionable taste, if any.
Leslies Pool Shock"