Have you tried adding a little DE to your sand filter? Backwash first. Start with a bout 1/4 cup, wait 30 and see if your pressure went up. The object is to determine how much DE is needed to make your pressure gauge go up 1 psi. Then just run your filter 24/7. When the PSI goes up five or six pounds, backwash and add DE again.

Also put a "skimmer sock" in your skimmer. Between the two your water should go clear in a few days.

Carl