We don't close our pool for the winter, but just minimize operations and run time on the pump. I clean ours in the fall, and at open. It's never gotten over 1lb over new pressure (12 psi with waterfall running full open). I don't use the floor jets when checking pressure because it varies depending on how many jets are operating at a given time.

I simply use a hose with water, but we've had no scale for 4 seasons running. I have a dual cartridge setup; 1 200sqft filter, and a 100sqft filter. The filters still appear to be in good shape.