Quote Originally Posted by Watermom
You can try 10, but if you don't see progress, bump it up to 15. Or just go on up to 15. With cya of 40, that would be fine. But the key here is to sustain the high reading. Don't let it yo-yo up and down. I don't know too much about phos-free, but the general consensus around here is that for most pools, you don't need to worry about phosphates.
Thanks. I'm going to keep it at 15......again! I just can't for the life of me figure out that after keeping it close to 15 for a week, brushing backwashing, etc that after having the solar cover on for a week it started getting algae on the walls. The water was still clear, so I guess I caught it early.