High chlorine levels will degrade a solar cover and make it brittle. Sunlight helps break down CC. I'm sure there are other reasons, but sunlight should only account for 2-4ppm loss of FC per day if your CYA level is 30ppm or higher.
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Welcome to TFP! For a wealth of pool care information please check out our free Pool School. If you are in need of specific help then we encourage you to Register and ask us here in the forum!