Hasa Super Stain-Out Concentrated Stain Prevention + Removal 32 Oz P/N: 76121 HASA SUPER STAIN-OUT is primarily used to prevent staining which can occur whenever fresh water is added to swimming pools. Fresh water supplies typically contain some stain causing contaminants including metals such as iron and copper as well as calcium which builds up to lock in discolorations under scale. When HASA SUPER STAIN-OUT is added along with fresh water, it will hold these potential stain causing particles in suspension to inhibit stain and scale formation on pool wall, floor and tile surfaces. HASA SUPER STAIN-OUT can also remove existing surface staining. However, once stains are formed removal efforts may not be as successful as preventative methods would have been.