I have also had trouble this year with clearing up the pool, but all my numbers are good and water is clean, just not clear and a tinge of green. Figured out my wife was vacuuming the pool and was not vacuuming to waste, and the sand filter was literally pulvarizing the dirt, pollen and dead algae into a greenish solution. After I figured it out, we kept the kids out for a couple of days and let everything settle to the bottom, then vacuumed to waste and the water has been clear ever since. I also tried using a little DE in the filter as Carl suggests and that has been helping. But I have learned, vacuum to waste when using a sand filter!