I think I know the answer already, but I like to post to this trusted community for concurrence. We are noticing what appears to be "staining" under the pool light on the vinyl liner. It looks like the gasket around the light is deteriorated and is staining the liner. My husband took a closer look under water yesterday and says he can see water inside the pool light fixture, which I believe should not be happening. After doing some "Googling" - I think the gasket needs to be replaced and there definitely should NOT be water in the light fixture as that is the point of the gasket. Yes? Is this easy to replace ourselves or should I call our trusted pool guy professional? My husband is pretty handy with things around the house, but we normally have the pool professionals come in and fix things related to the pool. I did brush the stained area and it seems to be coming off and we can see some black flaking.