To avoid draining back our 24 ft. above ground pool over winter I put one of those block-off things in the skimmer opening, vacuumed all water from the skimmer, blew out the PVC return line and installed a gizmo device in the skimmer drain. I also put plenty of Teflon tape on the gizmo threads. However, when I checked yesterday, I found the block off was leaking and the skimmer had filled with water. Worse yet, the gizmo threads had leaked filling the return line with water. So obviously this ain't working too well! I'm wondering if there should be an "O-Ring" on the gizmo as ours didn't have one? Or would it be better to just use a PVC plug in the skimmer drain for a more positive seal and put a bicycle inner tube in the skimmer to prevent freezing? If I do that, I shouldn't even need the skimmer block-off thing. Any thoughts?