Today I began the conversion from Baqua to Chlorine in my 8000-gal AG Doughboy. After reading the how-to directions here, I bought shock from my local pool store. I use Jason's calculator and found that 1 gallon of 10% bleach would raise the FC level from 0 to 12, so I poured it in! The water turned a creamy yellow. After 2 hours I tested and found the FC to be 0.5. I poured in another gallon and just for grins, I re-tested 15 minutes later...FC=1! Still creamy yellow...what's happening?