Well used the TFP /BBB methods all last year and they worked great. Thank you very much for my new pool knowledge. I opened the pool last weekend and it was perfectly clear, best opening i have had with the mesh cover. Pool water clear and chems are perfect. But I have a little black "dirt" that keeps reappearing at the far points away from the returns each morning. Pool temp is around 60 degrees there are no CC's reading in the pool OCLT test was passed and again water is perfectly clear. I keep vacuuming up the "dirt" each am and it is easily picked up through the vacuum. Was considering black algae but don't think that is it. Not sure if it is pollen (Trees are just budding now and there is a yellow pollen ring around the waterline) or just fine dirt from the winter closing that isnt getting picked up by the filter. Since I have never opened the pool to these near perfect conditions I am not sure what to do. Usually I am dumping in barrels of bleach at this point in the season. I may add DE to the filter and pick it up that way or vacuum on waste to remove whats left. Any suggestions would be appreciated.