I'll try backwashing later on this morning and post the results. It's pouring out here today so I'm sure I'll need to lower my pool anyway. When I put the DE I didn't notice anything cloudy coming from the return but can't say that I really concentrated on looking.

The settings on my filter are: "filter", "backwash", "rinse", "winter", "closed" and "recirculate" Could recirculate be the setting that I want? I don't know the difference either between "winter" and "closed".

I put the 3 (50lb) bags of sand into the filter, the filter is a 150lb filter. The first time I backwashed I lost about 5lbs of sand.

I just looked out in the pool and the dust/dirt on the bottom of the pool looks to have some white mixed in with it. I added some DE yesterday. So hopefully we are on to something with the spider gasket.