Reduces dissolved toxins from fish waste. Works in any filter. Phosphate free. Keeps aquarium water crystal clear and ammonia free. For use in freshwater aquariums. Promotes fish health by improving water quality. Unique Blend Of High Grade Activated Carbon And Ammonia-Removing Media. The Activated Carbon Removes Dissolved Organic Waste, Colors, And Odors. The Ammonia-Removing Media Removes Toxic Ammonia Caused By Fish Waste And Organic Debris. 9 OUNCES