Green Hair

I'm in Southern Ontario Canada. Cold winters from December to March. The type that freeze lakes and pools. I have a 10 foot deep inground pool. I closed my pool for the first time myself this weekend but I hit one final snag. At the base of the skimmer there is a hole (underground pipe) that runs to the pump and there is also hole (another separate underground pipe)feed/intake pipe that runs from the drain of the pool to the skimmer area. I've drained my pool about 8 inches below the skimmer inlet plate. I've sucked all the water out of the pipe the runs to the pump from the skimmer base. But the pipe that runs from the bottom of the pool drain (10 feet deep at very bottom of pool) i cannot drain. The water flows up the pipe from the bottom of the pool and keeps flowing up until the water in that skimmer reaches the level of water in the pool At the bottom of the skimmer it has a threaded plastic plug for that pipe/hole. The pipe/hole that runs to the pump is a rubber plug that you force in and expand or tighten by turning a screw so they use different plugs yet are side by side holes. Because things freeze in this part of the world is there any way to prevent water from flowing up that pool bottom pipe? How can I be sure the water doesn't freeze in that pipe? If i don't thread the plug into that hole/pipe water just keeps flowing up. The bottom of the skimmer is about 16 maybe 20 inches below grade. All other pipes and equipment are drained and dry. Can anyone give me any advice about my situation? THANKS!!!!!