What happens if you run out of all that stuff?

What happens if you need to sanitize more than a quart of water at a time?

A pound of pool shock costs me around $7. It will make 453/75 or 6 quarts of bleach solution, which will purify a lot of water at 4 drops per quart.

Say you have (or found) a water buffalo. 400 gallons, how are you going to insure the water in it is potable? Just because you filled it with tap water doesn't mean it will stay clean.

(By the way, to test water, buy a pool test kit (or at least the orthotolidine or OTO in one), and get a sample of water in a clear glass. Put a drop of the OTO in the water, it should turn yellow. If it doesn't, no chlorine).

That Pur kit is good for 7.5 gallons of water and costs the same as 2 lbs of pool shock. My filter cartridge is only good for 200 gallons and costs as much to replace as 6 bags of pool shock.

And, since regular liquid bleach will deteriorate rapidly, it might be a good idea to have a method that will last longer.