Thanks all for the responses. I have a Haywood cartridge filter which we purchased a few weeks ago. I also thought of pollen. I have been cleaning the filter twice a week now because the filter is getting dirty. I was cleaning it once a week. I brush the sides and bottom of the pool every morning when the pump comes on. Otherwise the water looks great. As long as the pool water looks clean I am a happy camper. I will just keep brushing as I could use the exercise