Is draining a pool necessary when the CYA is over 120? I had a pool service with a reputable company and they let it get up that high. I had another service tell me it had to be drained in order to bring it down. I want to be compensated by the old service company so I can pay the new service company. The chlorine was 10+ and the ph was 0. It’s a fiberglass finish pool. Thanks for your input, Donna