Thanks, the de is coming out of the returns. The grids felt like they were properly seated in the manifold, and the unit came with a new air bleed tube\ screen. After running it for a few days, notices large amounts of de on the bottom of the pool. We had a pool person come out and check the filter. He said he couldn't find any problems, vacuumed the de out and said it was working fine. Looked like the flow had increased quite a bit on the return line. We backwashed and recharged the de filter, and now seeing the same problem - de coming of the return.