I've seen posts from people complaining about having algae problems after leaving the solar cover on for a week or so. I always figured it was probably just neglect, but I saw it happen over the weekend to a friend's pool and now I wonder.
Buddy from work called me and asked me to check his pool yesterday afternoon. He's overseas for 3 or 4 weeks, and his sister emailed him and said the pool was green when they rolled the cover up Saturday. He has a SWCG and was running the pump 10 hours a day. His numbers were about perfect although I couldn't check his salt, and nothing seemed unusual that might have caused it. The pool was just a little green, with no algae on any surfaces. I shocked the pool and set his pump to run continuously and told his sister to check it this afternoon and call me.
Got me to thinking that maybe it was the rainwater on top of the cover that had grown the algae. Actually, any water that gets caught on top of the cover would be subject to algae growth since it can't circulate and is exposed to plenty of sunlight to consume the chlorine in it.
I'm thinking if I go back that I'll rinse the cover off with pool water to both expose the surface to chlorine and to flush any algae into the pool where it can be dealt with.
Anybody have any thoughts?