Controls many types of algae in marine and reef aquariums. Will not harm marine fish, coralss, or other invertebrates. Effectively controls Green algae, Red slime, and Brown algae in marine aquariums containing live corals, invertebrates, and fish. - Reef safe - EPA registered - Use weekly to control algal growth and reduce aquarium maintenance - Does not discolor water or cause foaming - Treats up to 2,400 gallons