I am using the shock process detailed on Pool School, and this morning I went out to test my FC so At 0740 it tested FC-6 CC-0. I added the recommended bleach as per the pool calculator. Then at 0910 it tested FC-13, CC-0.5. I waited until 1210 and it tested the same. I have added enough CYA to bring it up to 30 from 0 so my FC shock value should be 12, that has been my target throughout the whole process. Is this a concern or is this normal?