Quote Originally Posted by Slachey View Post

Any ideas as to why it greened up so quickly. Its only March!
I had know idea algae had a calendar. Nutrient rich water and low chlorine is sure to allow algae to bloom albeit a little slower when it cooler. No cover and some nice sunshine and away you go.

I put my pool away in September with water temp at roughly 60F and won't open it again until June, done this several years and not had a problem but I have low nutrient water and a good dark cover, maybe you need to spend a little or keep the chlorine level up.

Over here we tend to say algae won't grow below 50F (10C) just to be sure I do add chlorine and run the filtration 24 hours before I remove the cover. Sunlight is one component algae needs to bloom.