Third season owning a pool, first two went well. This year I kept the pool open year around and when I had sudden algae after a storm I shocked it and nothing happened. At this point I took my water in to a pool store to be professionally checked. Several hundred dollars later and my pool is greener than before. So now I am using the internet and your forum to try and combat the issue. I made another post about satbilizer at 120 ppm so I hope I'm on the right Trail. I'm not sure how much of the 33,000 gallon pool I should drain before starting over. Any tips?