I'm wondering what mistake I made changing out the air relief valve on my DE filter. The air relief valve began to leak recently, so I replaced it. It was successful, and water no longer leaks from the top of the filter, which is great, but I think I missed a step. I turned the pump off, and removed the air relief valve completely. Immediately I could hear water draining from the filter and I saw through the clear plastic on the top of my pump that the pump strainer basket was filling with cloudy DE laced water, and (I think) that water flowed back into my pool through the return jets. Oops!! Was I supposed to set the filter to backwash or winterize beforehand? I don't imagine I'll have do this procedure often, but I'm curious.