I have a Hayward sand filter that never needs backwashing. I guess I could attribute that to our clean Oregon air, but with tons of pollen and dirt settling on my solar blanket, we all know that isn't true. When I have backwashed, vacuumed, or otherwise pumped water to waste (the street around these parts), I notice a small amount of sand on the street. I suppose this is normal but I have no idea, since I have only been here for 5 seasons, how many times this has been done. I never notice any increase in pressure even when I put a small amount of DE in the skimmer. The water looks clear but if I leave my Polaris off for a few days, I do see sediment on the bottom. I am beginning to think my filter is very low on sand. Do you agree?