We have just bought a home with our first pool (inground) and it came with a Polaris 280. The booster pump is wired in with the main pump so it won't run unless the main is on. The question we have is with the Polaris attached to the pressure outlet on the side of the pool and the booster pump off, it still moves around, albeit slowly, due to pressure still coming out of the outlet. Is this normal and will it hurt anything? I don't remember the HP of the main pump right off hand, but I know the pool guy was surprised it was as large at it was for our size pool (~35x15 bean shaped and 5' deep at the deep end).
I'm sure we'll have a ton more questions as we go along.