API ALGAEFIX algae control effectively controls many types of algae in aquariums and will not harm to your fish or plants when used as directed. You can use ALGAEFIX algae control as part of your aquarium maintenance routine to control the formation of new algae. Weekly doses will control algae growth and reduce aquarium maintenance. CAUTION: Do not use with freshwater crustaceans including shrimp, crabs, and lobsters. Safety Information Please Read Instructions Before Use Directions Add 1 ml. for each 10 gallons or 5 ml. for each 50 gallons of aquarium water. Repeat dose every three days until algae is controlled. Siphon or scrape any dead algae from aquarium. Once algae growth is under control, add one dose per week. Weekly doses will control algae growth and reduce aquarium maintenance.