I've tried searching this one and have found very little information on it anywhere...I did see one post at Troublefreepool.com that talked about it resulting from a higher pH over a long period of time. They recommended lowering the pH to 7.0 for a while and allowing the buildup (of calcium?) to dissolve. The buildup does come off with some serious scrubbing, but I'm not sure I want to rent scuba equipment so I can do the entire floor of the pool (16' x 36' from 3' deep down to 8') Anyone have any recommendations?

DE filter/Hayward pump
FC 16
CC 0
TA 80
pH 7.8 (I usually run mine a little high and it works for our pool)
CYA 85 (again, a little high but perfect for our SETX full-sun climate)
CH 250