Im trying to winterize my pool, and the one skimmer keeps filling back up with water. The water level is dropped, return lines plugged, but the one skimmer (which i wanna say is connected to the main drain) refills, just to where the line opens up into the skimmer basket area. I've tried sucking the line, blowing the line, and positioned the jandy valve in all 3 positions. Im at a loss, i feel like I'm doing what all the YouTube videos are saying...