]I have a CYA level of 100. I've been fighting Algae this summer and I'm sure that the high CYA level is why. At the end of the season I plan on emptying out some water. It is a 26,000 gallon pool. #1: Can you tell me how much I should drain out? #2 And, how can I prevent the CYA level from getting that high again since my automatic chlorinator is Trichlor? The pool store sold me conditioner to put in the pool which I did put in in 2012 and 2013 but knew not to put any in this year, but my CYA is still 100. According to the charts on this site, I need to shock my pool to a FC of 39 to kill algae and 57 for mustard algae. I'm afraid to shock my pool to FC level of 39, let alone 57! #3 Will this not hurt things? And I know my target FC should be 12. #4 Is it safe to swim with a FC of 12? #5 With a CYA level of 100, what FC level is safe to swim in? I have no CC. pH 7.5 and Alk 92. I use the TF 100 testing kit. My water is currently crystal clear but when I brush certain parts of it, I can see some yellow/green powdery stuff. I will be doing the OCLT tonight to see how I'm doing. I have a pool party planned this weekend!!
Thanks! I'm just trying to get through this swim season, will empty out pool when I close it this fall and start fresh next spring. Just would like some guidance until I get there! Sorry for all the questions but thanks so much for this wonderful site!