Works instantly to remove the toughest waterline stains, algae stains, rust & gas exhaust stains. Use on fiberglass only. Will not harm gel coat. 1 GA Bottle Works instantly to remove the toughest waterline stains, algae stains, rust & gas exhaust stains. Use on fiberglass only. Will not harm gel coat. 1 GA Bottle SKU: MK20128 Loading... Availability Loading... Selected quantity should be in between 1 and 99999. - Enter Quantity + Add To Cart