there is this really hard green buildup on the bottom of the boat. I tried to pressure washer it off, but it wouldn't budge. Does anyone know of a good product to use to get this off? I enclosed a picture if it will help. My dad said something about using an acid, but didn't know what kind he had used in the past. Thanks!
StarBright makes a hull(bottom) cleaner that does a good job on glass. Dissolves brown stains without rubbing. Has acid base, will clean hands REALY Well, wear gloves and eye protection as per instructions.