CYA disappears over the winter

[Watermom]

You are fortunate that when your water gets to that temp that you don't have algae problems. We used to tell people that if your water temp was below 50, you didn't have to worry about algae. That was, until Poconos and I both had very slight algae when the water temps of our pools was in the 40s. Al actually has a pretty cool picture of algae growing in his pool under ice. I'm gonna see if I can find that pic and if I do, I'll edit this and put it in here. (or, I'll get Al to do it.)

Al's Edit: I never throw anything away. Don't know what the water temp was down at the bottom but it had a good layer of ice.
0004843AlgaeUnderIce.jpg