How important is it to keep the water line below the return jets? I had it lowered to blow them out, then put plugs in. But we have since had rain that caused the water level to come back up to partially cover the returns - and it will probably cover them completely if we get more rain. I am in Michigan and the pool will definitely freeze. Should I pump more water out so that it is below the returns when it freezes? Or does it not matter?