Hi! My name is Amy. I moved into a home last August with an inground pool. I have a 15x30 pool with a STA-RITE 3 series filter system. I need to get the top part off to get to my filter cartridge to clean it. Full of algae.. lid won't come off. I've tried everything the company that installed it to get it off. No luck. Ready to throw in the towel, lol. Trying to do it without paying someone. Any suggestions?