Gordon's, gallon, ready pour formula, pondmaster seclear algaecide & water quality enhancer, kills all types of algae including toxic blue-green algae, controls planktonic, filamentous and plant-like types of algae, helps stop algae before it starts by reducing the phosphorus available to fuel growth, fewer applications and lower use rates are necessary when used preventatively (compared to traditional copper algaecide treatments), for use in still or flowing aquatic sites including ponds, lakes, reservoirs and potable water sources, will not harm fish or livestock when used as directed.