Can anyone guess what might be happening here? Every summer about early August I start to see cloudiness develop. My pool is 24000 gallons. I pump 60 gallons per minute for 12 hours a day. I keep my chlorine (SWG) at 5ppm or higher. My CYA is 50 ppm, pH is 7.5, CH is 110 ppm, Alk is 70 ppm.
Three things change with my pool around the beginning of August: The pool is mostly in the shade almost all day long, (just two hours of late afternoon sun). I put the cover on the pool at night to keep the temperature up (78 is the best I can do with the solar heater going). And the pool is used much less, (maybe an hour or two on the weekends).
I have to vacuum the sides of the pool at least twice a week because the south side, (the shady side), develops a green film, (presumably algae). The neighbor's very large tree to the south of the pool provides the shade as well as periodic droppings, (very nice).
I thought that keeping the chlorine at 5ppm or higher would keep the cloudiness from happening, but I was wrong. Is there some type of algae that thrives in the shade that I should specifically be treating? The sunny side has no green film.