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: Keeps freshwater and saltwater aquariums clean and reduces maintenance Consumes sludge to help keep gravel and decorations cleanAdds beneficial bacteria for a healthy aquarium Use weekly to maintain a clean, healthy aquarium Includes: Contains one (1) API STRESS ZYME Freshwater and Saltwater Aquarium Cleaning Solution 1-Gallon Bottle Intended Pet(s): Fish Product Dimensions: 7.125 x 4.125 x 11.5 Capacity: 1 Gallon Directions: Use weekly for a healthy, clean aquarium and to maintain a strong biological filter. Shake well. Add 5 ml per 10 gallons (38 L) of water. For new aquariums and to help boost the biological filter, double the dose at start-up and use for 2 additional weeks. Caution: Keep from freezing. Do not store above 120 degrees F (49 degrees C). API Stress Zyme Aquarium Tank Water Conditioner, Size: 1 Gal | PetSmart