Ok, here goes.
Pool company came and closed my pool last week of October. Water looked good and clear. Checked a couple weeks later and still clear. Reason I checked is that we have lots of trees so leafs still get under cover from front opening. The water temp is well below 60F. Today, it's 42F.
I opened the cover 2 weeks ago to find what I thought was ice forming on top the water. Well, it's not ice! It's a foam that when scooped with the skimmer looks light tan and scummy. I assume I had an algae bloom at some point. Not sure how as the water temp was probably below 60. In either case, I now have a mess. Water is green with no visibility. Scum floating in patches on the top. The pump and lines are full of antifreeze and plugged for the winter so no filtration.
Should I do anything about this until spring? My CYA levels were 90-100 when I closed. I'm doing periodic partial drains and refills over the winter in order to get that down to 30-40 in hopes FC will be more effective next year.