This pool is missing it's vacuum cover. It's snapped off. I removed what's left of it and screwed a new one in. It quacks! That means it makes a repetitive noise when the pump is on. I can't turn off the vacuum line because the only two ball valves going into the pump are partial submerged under soil (I could dig them out) but I'm wondering could one be for the main drain and the other for the skimmer or would it be a given that one is for the vacuum line. ideally I would just like to just plug the vacuum hole and be done with it.