I've got a mid-80's fiberglass pool slide that's long overdue for an overhaul. The surface is chaulky, no longer slick, and starting to stain. I'm planning to strip it with a DA sander or sand blaster and apply new gelcoat. Question is: I've been told that boat gelcoat isn't suitable for pools (weather + chemicals) and that I need to buy special, more expensive pool gelcoat. Is this true? Anyone have a good source or any particular methods, tips, tricks, etc?