Hello, I’m new to the group and a new pool owner. I’ve quickly engulfed myself in the TFP method. Everything is great, except... There is sand in the bottom of my pool. Decently sized grains. When I vacuum them up, they bypass my cartridge filter somehow and you can literally see them come out of the returns and settle on the bottom while still vacuuming. The cartridge picks up smaller particles no problem. Any ideas?