HTH Surface Cleaner works on tough crusty waterline stains. It is a thick, powerful gel, so it sticks to every curve of your spa. Surface Cleaner is safe for all types of spa surfaces. It is great for calcium deposits. For tougher stains, use a soft brush, or our Spa Mitts.

Manufacturer's instructions: HTH Spa Surface Cleaner can be used whether the spa is full or empty. Wet the surfaces to be cleaned using water from the spa. Apply the product using a sponge or a waterline brush. Leave to penetrate for at least five minutes. Brush any ingrained deposits. Rinse with water from the spa. Repeat the operation on stubborn deposits.