On giardia and chlorine:
Results of these experiments at the three temperatures studied can be summarized as follows: at 25°C, exposure to 1.5 mg/liter for 10 min killed all cysts at pH 6, 7, and 8. At 15°C, 2.5 mg of chlorine per liter for 10 min killed all cysts at pH 6, but at pH 7 and 8 small numbers of cysts remained viable after 30 min but not after 60 min. At 5°C, 1 mg of chlorine per liter for 60 min failed to kill all the cysts at any pH tested. At this temperature, 2 mg of chlorine per liter killed all cysts after 60 min at pH 6 and 7, but not at pH 8. A chlorine concentration of 4 mg/liter killed all the cysts at all three pH values after 60 min, but not after 30 min. A chlorine concentration of 8 mg/liter killed all Giardia cysts at pH 6 and 7 after contact for 10 min, and at pH 8 after 30 min.
From FEMA:
Clear clean water: add 8 drops of unscented household bleach per gallon
Water with an obvious happening party therein: add 16 drops per gallon.
Our group (3 to 5 persons) packs about a 6 ounce squeeze bottle of bleach on all of our wilderness trips. We usually have about half of it left after trips of up to 3 weeks. Dip it from the source, treat, wait a bit, and have at it. Much quicker than neighbors that spent about 40 minutes a day filtering water.
Last edited by 1minute; 10/05/18.
