This spring I installed a used AGP. After everything was filled & running, I noticed that the skimmer box has some small hair line cracks. I was able to seal them with pool putty and I have been fine with it all year. Now that I have closed the pool and drained down below the skimmer, I would like to replace the entire skimmer in the spring. My concerns are about the liner. When the pool installer put the liner in, he pulled down to tension the liner to keep it tight. What will happen to the liner when I take the screws out that go through the liner into the skimmer? Will the liner move up or down or stretch in some way or possibly tear? What is the chance of not getting into trouble? Should the water level be as high as possible or very low? Anyone ever replaced their skimmer? Thanks!