Tetra(R) Algae Control(TM) liquid is highly effective against green water as well as algae types that grow on the glass and decor. Our broad spectrum algae controls green water as well as blue-green algae, brown algae, hair algae or blanketweed. A precision dropper top helps you administer the proper dose to your aquarium. Can be used with ornamental freshwater fish and plants. Each bottle treats up to 1200 gallons.