I have DE entering my pool through one of the returns as soon as I add DE to the skimmer. (I add as a mixture of water and DE). I recently purchased a brand new Hayward DE grid thinking that DE may have been getting through the previous grid, but this has not fixed the problem. I also added a brand new multi-port valve and this did not solve the issue. The only thing left that I can think of is to replace the elbow arm inside of the Filter. I've checked and it does not seem to be cracked, but I don't know what else to do.
Does anyone have any ideas on what else I can do now that I've eliminated the grid and the multi-port valve as potential causes?