The Natural Hot Tub Company All Natural Filter Soak 16 Ounce Bottle Designed to deep clean spa filters by removing visible debris and impurities. Regular filter cleaning is the most important maintenance you can do to minimize the need for additional chemicals and maintain clean water. Use every 2 months to give your filters a deep clean, helping extend their life expectancy. This all natural filter cleaner uses enzymes with citrus to clean your filters without harsh chemicals. Each 16oz bottle makes 64 gallons of cleaning solution.