I can second that! Last year was first year after winterizing and my pool guy said to open early to avoid mineral deposits. So I opened early and waited a month and a half before predicted temps reached the point where it was swimmable - but my water was clear! This year we waited until Wednesday, 5/2, to pull off the cover - and wow, was it yellow-green!!! 4 gallons of bleach and 24 hours later (4 hrs pump time) and it was clear, but a little cloudy. Adding more bleach got better, but I probably have to up my CYA since that went to zero last winter (and I haven't had time to do the full tests yet). BBB, it works! (Then I get my SWG going and don't worry the rest of the year except for muriatic acid!)