There are many preparedness blogs that discuss using hypochlorite to make bleach, but I had to wade through the differences between sodium and calcium hypochlorites and dosing amounts. I found the sources below and decided on this method.
Many campers use bleach for water purification, but bleach degrades over time, so it only has an effective shelf life of 6 months to a year. Dry High Test Hypochlorite (HTH) has no shelf life, and its cheap – a one pound bag (that will purify about 10,000 gallons of water) is about $5.00. I spent a little more ($24.00) and bought a five pound jug (which is a LIFETIME) supply because it can be resealed.
I will tell you though that this is not a perfect solution, this stuff is a powerful corrosive and if you don’t store this properly you WILL have problems.
Only use HTH Pool Shock that does not have any algicides or fungicides. Ingredients should reads CALCIUM hypochlorite and inert ingredients. Use a brand with at least 73% Hypochlorite.
For this video I used Poolife Turboshock, but feel free to use any brand you wish as long as it fits the perimeters above.
Before you begin mixing any chemicals in any way, please follow basic safety precautions. Make sure you do this in a ventilated area. Have plenty of water to dilute any mistakes. Wear eye protection for splashes. Lastly always mix the powder into the water NOT the other way around.
Add and dissolve one heaping teaspoon of high-test granular calcium hypochlorite (HTH) (approximately 1/4 ounce) for each two gallons of water.
The mixture will produce a chlorine solution of approximately 500 mg/L (0.0667632356 oz per US gallon), since the calcium hypochlorite has an 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 oz.) of stock chlorine to each 12.5 gallons of water to be disinfected.
To remove any objectionable chlorine odor, aerate the water by pouring it back and forth into containers to add air.
Common household bleach (unscented) contains a chlorine compound that will disinfect water. The procedure to be followed is usually written on the label. When the necessary procedure is not given, find the percentage of available chlorine on the label and use the information in the following tabulation as a guide.
(If strength is unknown, add ten drops per quart of water. Double amount of chlorine for cloudy or colored water)The treated water should be mixed thoroughly and allowed to stand for 30 minutes. The water should have a slight chlorine odor; if not, repeat the dosage and allow the water to stand for an additional 15 minutes.