Not sure what I'm not doing wrong. Had cloudy, algae caused problem months ago. Shocked it. Fixed problem and returned to crystal clear. But, even though I kept the chlorine level within 2-8 over next week and a half, algae came back. Repeated the process but problem returned within a week and a half even though I kept chlorine within recommended level, most times at the 8 or 9 level. Repeat again.
One problem I also have had recently is trying to keep CYA up but I'm not sure what impact this has. Some months ago, CYA level was at 0. So, added 7 lbs of CYA. CYA level stayed around 30-50 for awhile but after the latest algae attack now notice it's back to 0. Currently adding another 7 lbs. Have been running pump, vacuuming (Dolphin premier) and back-washing regularly. My questions:
1. is this algae recurrence unusual? and if so, any ideas what I'm not doing correctly or should also be doing?
2. does the low CYA have an impact on algae formation even though I keep the chlorine level within range?
3. I've been doing this for years and haven't had this many algae problems until recently. However, I've noticed that I need to keep the chlorine level at 8 or slightly higher or algae returns. Is it ok to keep it this high? How about even higher? Would keeping it at 10 be that much of a problem for swimmers? Could it be that more sun in Hawaii means I need to keep chlorine at higher levels?