I am considering replacing an old Polaris 180 suction cleaner with a Polaris 3900 Sport (will use existing booster pump). The existing return opening is about 1 inch and is only a hole in the side of the pool so it has no threads in it and the old Polaris 180 connector/fitting apparently was just twisted into it. The Universal Wall Fitting for the Sport is supposed to be 1.5 inch. I don't know if that is the threaded end or the Quick Disconnect female end. Does anyone know? Thank you.