The live bacteria in API Stress Zyme Aquarium Water Conditioner help create a biological filter that breaks down organic compounds to keep the environment clean. 300 million bacteria in each teaspoonful help break down organic compounds to prevent dangerous aquarium conditions, such as low oxygen levels and ammonia and nitrite poisoning. This process helps keep the aquatic gravel clean and the filter active for improved water quality and living conditions, which aids in creating a safe and comfortable environment for your pets. Features: Aquarium additive containing live bacteria enhance the development of a biological filter that cleans a dirty aquarium Breaks down organic compounds that cause dangerous conditions, such as ammonia and nitrite poisoning and low oxygen levels, to help improve the safety of your aquarium environment Keeps the biological filter working properly to help keep the aquarium gravel and filter clean, li>Water quality and living conditions are improved when used on a regular basis to help ensure your aquatic pets' health Harmless to humans, pets and aquatic plants Each teaspoonful contains approximately 300 million bacteria in a dormant state that become active when added to the aquarium Includes: 1 Bottle Intended For: Effective with freshwater tropical fish, marine fish, invertebrates and coldwater species, including Koi and Goldfish Material: Liquid Size: Available in 4 oz, 8 oz, 16 oz and 1 gallon sizes Instructions: For new aquariums, on the 1st, 7th and 14th days, add 2 tsp. (10 mL) for every 10 gal. (40 L) of aquarium water. After the initial 14 days, add 1 tsp. (5 mL) for every 10 gal. (40 L) of aquarium water weekly. For existing aquariums, add 1 tsp. (5 mL) for every 10 gal. (40 L) of aquarium water weekly to maintain good water quality and filtration. Shake well before using. Caution: Does not require refrigeration; keep from freezing. Do not store above 120 degrees F (49 degrees C). Size: 1 Gal.