A biological filter additive containing live bacteria that improves the development of the biological filter and helps keep a naturally balanced aquarium. New, more powerful formula works faster and cleans better. - Helps reduce toxic ammonia and nitrite - Helps clean a dirty aquarium - Contains over 300 million live bacteria per teaspoonful - Contains 5 beneficial bacteria strains, each specifically selected for its unique role in the development of the biological filter - Treats up to 7,600 gallons.