Update... I took the borates up somewhere north of 50 (not sure exact level), and I held the FC at 20ppm for last 10 days. I've been brushing almost every day and also set the Polaris to run 6 hours per day. The filter pump is running 24/7.

No sign of algae anywhere. But I'm guessing that could be due to the excessive brushing and Polaris run-time. So, as of yesterday, I'm letting the FC come back down to 8-10 and I'll stop brushing for a couple days to see what happens. I also reset the filter pump and Polaris to normal run times (12 and 2 hours respectively).

So far, so good. We've been swimming with no ill-effects at 20ppm, and the water looks fantastic.

Thanks for all the help. If the algae returns, I'll update again.

By the way, any suggestions on how to get the CYA down to a more normal level? I think I'd like to keep it around 50-60.

Mike