Opened the pool, adjusted the PH, and CYA was at 65. Pool was a bit cloudy but not much and there were areas of a light green brown on the bottom. Slammed the pool to 40 PPM by accident and kept it there for two full days while constantly brushing and using chlorine generator to keep it there. Shut the chorine generator off in the evening and it remained at 40 PPM. I have a cover and the weather was bad so I left the pool covered for the last 4-5 days without the generator running and the level is still at 35 PPM. The patches of greenish brown stuff have reappeared ! This happened all last year so at this point I don't see how it could be Algae. The pool is crystal clear.