[jimpick]

I would store Calcium hypochlorite if I were you it’s easy to transport as a bag will do about 10,000 gallons, it’s cheap, and if stored right last for ever.

Go here: http://www.survivaltopics.com/survival/better-than-bleach-use-calcium-hypochlorite-to-disinfect-water/

It will show you how to use it.

[djf]

If you have a farm supply store near, check out a gallon of gentle Iodine.

Antiseptic solution. Won’t degrade.
Two or three drops per quart, then let it sit for two hours or so and you are good to go.