I recently moved to a new home with an above ground pool. It has a Hayward Turbo Cell GLX-CELL-5. I started to get the pump and everything set up last night, but found I was missing the flow sensor. I don't believe the previous owners left me one so either they weren't using one themselves or accidentally packed it when they left. My question is how important is the flow sensor and would I be able to get things going without it?