Blanket weed is a problem that affects most ponds (particularly those which are UV filtered) the rapid growing filamentous stringy algae can spoil the appearance of the pond. It will also clog pumps and filtration equipment. Pond balance is a unique non-algicide plant friendly formula ensuring that no harm comes to any other pond plants, fish, filtration bacteria or water using wildlife. Pond balance does not affect plants because it works by making unavailable a nutrient only required by filamentous algae (blanket weed) and thus literally starves it out of existence. Pond Balance also contains plant stimulants and so helps establish a naturally balanced pond. Standard pack treats 6.819 litres (1,500 gallons) 500 gallons 3 times. Pond Balance needs to be applied once every 10 days for the first 3 treatments, there after it should be applied once every month. Kills Blanket Weed Harmless to pond plants, fish, filtration bacteria or water using wildlife.