HTH filter cleaner helps your swimming pool filtration system work more efficiently which keeps water looking clean and clear and improves the filter lifespan. Use this filter cleaner on all types of pool filters including cartridges, D.E. and sand filters. This powerful formula is simple to use and works overnight on all pool types including salt water systems.• Prevents copper and other metal stains• Extends life of filter• Helps clarify water• 0• 0