It took me a year to finally cut the liner, the skimmer was installed, but had solid liner over it. Last year, after fighting the maple helicopters, apple blossoms, finally threw in the towel, drained down the pond, about a foot, and cut the liner. So far it is doing great. I tend to over seal.........used the gasket, used goop, used extra screws, gooped every edge, place water could potentially seep between the gasket and the liner. Let it dry for three days before I refilled the pond.
No leaks!
I stuffed the skimmer with bubble wrap to displace the water in preparation for the winter that never really hit. At least the water could not freeze and hurt the skimmer.
That skimmer has been a great help this year, collecting basket after basket of maple seeds.