I've been keeping cl in the 30+ppm range for about a wk. According to the Best Guess Chart with a CYA reading of 40. I give up on getting rid of it totally. I'm taking down the pool in 10 days and will just keep my cl at 30+ until I drain. When it's time to drain I plan on draining halfway maybe a bit more and adding an algacide, letting it sit for 24 hrs. to make sure anything still growing is dead. Finish my drain, scrub, dry and pack.

Strange thing: Since I started using this solar cover my cl has increased by 1ppm daily. I haven't added anything since Tuesday! My CC is still at 0.
No increase in the algae either. The whole situation has left me shaking my head.