How much of the pool shock do you add to a gallon of H2O to purify it? I know that when you put too much bleach into your water it tends to run out the other end rather quickly...........LOL
OKC9 has got it down on the pool shock recipe. And the Big Berkey system is basically what you and I are doing with our 5 gallon buckets and the ceramic candle filter.
Here's a vid on a homemade Berkey system:
http://www.youtube.com/watch?v=w21d_YXiOOU