It is inside the grids again. Happened when I opened the pool, and not knowing if the manifold was broken or if there was a tear in the fabric I got a great deal on a new filter. Is it possible that the multi port valve is not working right and directing the water into the grids and not outside the grids? I have the valve set to filter when adding the de. I took the filter apart because on backwash water hardly came out and what did was clean.