Total noob question, but I'm currently replacing my pool light and when I separate the lens from the casing, I quickly realized that the casing was full of a greenish/brown sludge. It looks like grease to me, but I can't for the life of me figure out why anyone would put a large amount of grease inside a pool light enclosure. My only other thought is that it might be some form of algae, but I've never seen it so concentrated like this. I've attached some pictures so you can see what I'm dealing with. Thoughts?