API Marine Algaefix controls many types of algae growth in marine (saltwater) and reef aquariums, including Green algae, Red Slime, and Brown Algae in aquariums containing live corals, invertebrates, and fish, and does not discolor water or cause foaming. API Marine AlgaeFix should be used weekly to control algae growth, as part of regular care to reduce aquarium maintenance. API Marine AlgaeFix is an EPA registered product, and will not harm any live element of your saltwater or reef aquarium.