Jump-start your biological filter with Stress Zyme. This filter additive contains live bacteria that improves the development of the biological filter and helps clean a dirty aquarium. Because organic pollutants hinder the development of beneficial nitrifying bacteria, Stress Zyme also contains additives to break down these wastes more quickly and efficiently. This organic pollutants also promote the growth of disease-causing organisms in your aquarium, making Stress Zyme a disease inhibitor as well. Water quality and living conditions in your tank are sure to improve with regular use of Stress Zyme. Contains millions of natural beneficial bacteria in the dormant state, which activate in your freshwater or marine aquarium.