I am hoping there is help out there. I have a main drain plumbed into my skimmer and I need to winterize it. We have tried blowing air into the hole in the bottom of the skimmer feeding the main drain but nothing happens. We have also tried sucking the water out of this pipe but it fills back up. Because we live in a cold climate that can see -20 in the winter, we want to ensure this line is air-locked but we don't know how. Any help out there?