API MARINE STRESS ZYME bacterial cleaner contains millions of live bacteria that consume sludge and organic debris, reducing aquarium maintenance by keeping live rock, coral, sand, gravel, and aquarium glass clean. May be used weekly to reduce aquarium maintenance and maintain a strong biological filter. Making API MARINE STRESS ZYME bacterial cleaner a part of regular aquarium care ensures an active biological filter, a cleaner aquarium, healthier fish, and good water quality. Directions Add 5 ml. per 10 gallons of water weekly