I'm a fairly new owner of a house with a vinyl lined pool. Every time I swim, I can't help wondering how the parts that the vinyl liner were cut out for- skimmer, main drains, returns, and especially the light and light niche- seal and keep water from leaking out. I've done numerous searches, but I mainly come up with websites selling products and not much description on the actual construction details. Is anyone aware of a good website that shows detailed construction pictures of pools and the areas/materials behind the walls?