Help I'm a new pool owner and thought I was on top of things until last Saturday. I woke up that morning and tested for FC, PH, stabilizer, and combined Chlorine and everything was good. When I returned home around 5:00 there was a small green tint to the water in the deep end. Seeing this I shocked the water and waited till the next morning to find the whole pool extremely green. Seeing this I assumed I had green algae and took a water sample into the pool store Monday morning where they found that all of my levels were good except for the Phosphate level being 300. They then gave me an Algecide and more shock. I was told not to do it until after the big rain we were getting on Tuesday. I then waited for the rain to stop and did the Algecide and another round of shock on Tuesday evening. My chlorine levels have been 5-10 the whole time as well. I also cleaned my filter cartilages on Sunday and again yesterday (Thursday). Well it is now Friday and I do not see any difference. I called the pool store and explained the situation. They wanted another sample which I haven't done yet. They also told me to put a water clarifier in to see that works. I'm now really questioning if it is green algae or something else. Please advise.