I have a katydian silver impregnate cermaic filter, that doesnt use any idonine which messes with thyroid, and I cant use city drinking water is what I meant about Cholrine. Cholrine is a very unstable purifier in the woods because the shaking in a backpack renders cholrine and bleach useless. I normally try to camp near springs now and just drink that water straight, dig egyptains wells, tap tree saps in early spring, and use a turkey oven bag in direct sunlight for about 6-8 hours after debris filtering. a turkey oven bag fits easily in a wallet ad you can cook in it as a pot as well. Make rock oven, the lay a cirle of rocks on top flat rock, add sand or mud, lay over turkey bag, and you got a crock pot for cooking that literally fits in your wallet.