OK, so what is this stuff?
We don't close for the winter.
About a month and half ago I did the whole Ascorbic acid treatment thing.
Brought my chlorine levels back up.
Brought my salt levels back up (water was about 62F at the time.
When the water temp hit 65 I turned on my SWG.
Water seems balanced, but I have these appearing all around the pool, just under the water line.
Here is closer look.