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 …




Letter from The Army Aviator Re: Katadyn Versus Berkefeld Filters

Here are some useful specifications: Katadyn Drip Filter 0.2 micron ceramic depth filter (Note: This is the ABSOLUTE filtration specification, NOT the Nominal filtration rating.) British Berkefeld Big Berkey With filtration rating efficiencies of >98% down to 0.2 microns >99.9% at 0.5 microns >99.99% at 0.9 microns (Spectrum Labs). Note: Berkefeld’s ABSOLUTE filtration specification is 0.9 microns. (See the above line.) I ‘ve watched the PR advertisements regarding Berkefeld and just sat there shaking my head. I was sent some Berkefeld filter replacements which were touted as equal to Katadyn’s but a much better price. NOT! When I read the …




Letter From The Army Aviator Re: Polar Pure (Iodine Crystals) Water Purification Bottles

I checked and REI was cheapest @ $10.50 ea. Called my local REI and they had none, but they checked and found that they had 244 in their one and only distribution center. They quoted two weeks for delivery. I ordered my six. But assuming perhaps 2 in stock at each store [JWR adds: Unlikely, given recent events] that’s less than 500 available nationwide. That’s less than 1 for every 12 SurvivalBlog readers… I wonder which future ransacked city their distribution center is in? Hope it wasn’t New Orleans. Kind of unsettling how some things are really pretty scarce already. …




Letter Re: Where to Get Iodine Crystals?

Jim, Iodine crystals for disinfecting water are available as a trade product called “Polar Pure” from most of the regular backpacking supply places such as REI. It comes in a small bottle with a screened top, you fill it, shake it, and then decant a capful or two of the supersaturated solution into your water. The bottle has full instructions and also a thermometer so you know how long the water should sit before use. The cost was about $8 or so, last time I bought any. – “Doc” JWR’s Reply: A highly recommended product! One little three ounce bottle …




Letter Re: Where to Get Iodine Crystals?

The best water purifier for general carry is Iodine crystals. Carry them in a 35mm can, add water, shake and pour into the canteen. They last, like forever. But, because of drug manufacturing freaks, I can’t find anybody still selling Iodine crystals. Any ideas? JWR’s Reply: Unfortunately I don’t know any sources. Sadly, most of the hobbyist chemical supply houses are a thing of the past, along with true hobbyist electronics stores. Perhaps someone reading this blog knows a good source for Iodine crystals. The iodine crystal method works well. A few large crystals will practically last a lifetime. However, …