My TF-100 test kit is coming today so I can have readings later but I am wondering how I should treat this problem. I have crystal clear water but keep getting these spots on the bottom (see picture). They are brownish and sometimes have a greenish border. When I'm in and touch one with my foot it dissipates. When I brush the spots, it creates a brown/green puff. I put a skimmer sock in and that turns greenish. I don't see anything on the walls at all. Is this regular algae? Mustard algae? I should also add that last weekend (prior to my TFP days) I put in 2 bags of shock from the pool store and a quart of algaecide. After doing this, when the clear cover on the pump was turning green. I took it all apart to clean it. I had this problem last year too but not upon opening this year.