Well I still have a crystal clear pool which is a miracle for me considering I havent seen the bottom of my pool in almost a year. But my question is about CYA. I added 22 oz about 2 weeks ago and got a reading of 37ppms. Problem: I can hold chlorine all nite but from the time the sun hits it and evening falls..I go from 5ppms to .5ppms, do I add more CYA at this time? Other question is...I have read and used the sock method but I see where some are saying put it(sock) in skimmer and others say infront of the return, does it matter and is one way better than other?