OK, I had my water tested at Leslie's because I've had trouble keeping my Free Chlorine level up. Jasonlion said my CYA was non existent and that's why the FC wouldn't hold. I added 4 lbs of CYA 4 days ago and have been adding bleach every night but still can't get the FC over .5. By the way, I have a 16,000 gal in ground fiberglass pool with a SWG and chlorinator running at 100% for 4 hours per day. My numbers are as follows: FC: .5 / TC 2 / PH 7.2 / TA 100 / CYA 27 / and here's a new one for me, they said my phosphates were through the roof at 2500! I don't even know what that is or what to do to lower it. They guy at Leslie's also told me that my CYA level is only slightly low and should be holding FC just fine. He said I should use 2 - 3 lbs of non chlorine shock to "free up" the chlorine. Since I don't think those guys know what the heck they're talking about, I thought I'd come back to all of you knowledgable people here at TFP and see what my next move should be. Any ideas???