Letter: Disinfecting Drinking Water


Your articles have mentioned calcium hypochlorite. I went to the pool store today, and they had sodium dichloride.

Should I ask specifically for the first? I’m not sure if the girl behind the counter is going to know how to help me on this one. Thanks – D.

HJL Responds: We only recommend calcium hypochlorite, even though sodium dichloride is also used as a disinfecting agent. The pool shop should be able to order it for you. You are basically looking for a chlorine bleach solution to stabilize and disinfect your water. Liquid bleach has a very short shelf life, and the powdered calcium hypochlorite will get you that bleach solution with a harmless calcium sediment as a byproduct. When you mix a batch up, just let the sediment settle out. It is important to look at the label of the product that you are buying. Managing pool chemicals is a different process than disinfecting drinking water. You need to make sure that you are not getting any harmful additives in the product you purchase.