Letter from “Dr. November” on Disinfecting Water

As far as disinfecting water, rather than bleach I’d recommend calcium hypochlorite (available as swimming pool chlorine or shock.) It’s somewhat cheaper, easier to use, doesn’t taste quite as bad (it’s what the military uses in large disinfection systems), and if you get a pool water test kit (the basic one) you can measure the residual chlorine. Just mix some calcium hypochlorite with water in a plastic squeeze bottle and add to the water you want to disinfect: Take a small sample out with the test kit and get something between 5 and 10 ppm (7-8 ppm is ideal.) A one-pound bag of calcium hypochlorite was around $5 at my local grocery store, and represents enough water to treat a good-sized swimming pool full of water (BTW, don’t drink swimming pool water unless it’s been recently replaced, and then only if you can filter it.)
For smaller quantities of water (backpacking) I like Polar Pure, and then my compressed carbon block (non-ceramic) filter. Ceramic filters can crack if they freeze, and are somewhat delicate. – Dr. November