I can't recall what I did last year...(nothing new...can't recall a lot of things) We have three returns, plus the dedicated return. When using the Polaris, I think I used to close down all the returns but the Polaris one. When I do that, however, psi shoots from 10 to 20 and connections on my SWG unit and filter start leaking. I know psi needs to come up for the Polaris to function, but is that jump too high? I tried it with one of the other returns open, but the unit didn't seem to work as well.