Just like your bath, grease & body fats can collect at the waterline, which not only looks unsightly but can prove to be a breeding ground for bacteria. It is good practice to clean this off regularly using Fi-Clor Spa Surface Cleaner. This is specially formulated to clean away body fats & grease easily & quickly, & can also be used to clean the spa interior when it is periodically drained before it is refilled with fresh water.