I just bought a boat and it has been in a nasty lake for a couple of months. It has very hard water stains on the cav plates and hull. I have tried Ducky, Simple Green, and others with only moderate help. Anybody out there have a secret product or solution. It has to be safe for anodized plates, chrome and fiberglass. Any help would be great. I don't normally deal with this because my boats never stay in the water more than a few days.