Pool is clear, ph dropped to 7.2 from 7.6, ta 90 cya is 40 , put in 16 ppm chlorine to 1.5 already in last night to shock pool. and added 45 lbs of calcium chloride to increase ch. what has caused the fc to drop to 0 and ph to drop to 7.2? I did have several swimmers today! Going to add 2.75 gallons of bleach to raise chlorine to shock level again. Should I add extra or try to keep it at shock level until overnight chlorine loss test is successful? Thanks in advance! I am stumped by this one. I have been using the tfp method for years w/o this type of problem.