Quick intro. I'm in south Tx. 45000 pool. Pool is 3 years old. Plaster.
Recently I have been getting dime sized spots in my plaster all over the pool. They seem to be rougher than the rest of the plaster. The pool looks like polka dots now. My cya was very high at 260 until I did a couple of partial drains an refills. The rest of the numbers were always pretty much in range.
Here are my current numbers using a Taylor 2006 kit. Chlorine.
Calcium hardness 200
I switched to the bbb chemical method recently. Water looks great but the dots worry me.