our community pool is green again! (THREAD CLOSED HERE)

[Stierchen]

I am taking care of our community pool! Friday a week ago it started to turn green! I think it is Mustard algee.
PH was 7.4, TA 120, Chlorine 7.5. We put 23 jugs os 121 fl. oz. of bleach in pool on Monday night. It turned back blue on Tuesday. Backwashed and added 1,000 gal fresh water. Had to add 3 containers of Pro Team Reverse (2 lbs each) to get Chlorine below 10 ppm. Opened pool back up at 3.00 pm Wednesday and after a big rain Friday night it started again to turn turquoise and now it is almost green again. CYA level is 100. We don't know why it is so high. We use pro guard sticks (stabalized) in a chlorine dispenser. What are we doing wrong? PH today at 7.4, TA 100 and chlorine at 12 ppm. Please help!