Ultra Clear 41125 Biological Pond Clarifier, 32 Oz UltraClear works naturally and actually benefits the environment. Improves clarity, cleans the water, reduces organic build-up, and removes odors Prevents build-up of toxic ammonia and nitrite, making your pond a healthy place for fish Begin with one ounce per week to treat water garden pools up to 2500 gallon and after one month reduce to twice per month or as needed.