So, my sand filter pressure is normally around 20 and I backwash when it gets around 25 or so. tonight I noticed my returns weren't working, my SWG said no flow and the pressure on the filter was at 30. I've never seen it that high. I backwashed 5 days ago, but it is May and pollen is falling like crazy. I backwashed, turned everything back on and returns are normal, SWG says flow is good but the pressure on the filter is around 28. what do I do?