Last year I closed pool end of September when temperatures was in 60s day - 50s night. I’m going in for knee replacement September 11 with temperatures in the 70s here - NY Long Island - what should I do ? Shock pool on the 7th and put in poly algaecide 60 on the 9th. I don’t know what else to do. When opening it will be green. Just shock it again and run pump 24-7