This 9 watt UV smartpond® pond clarifier is ideal for use in ponds up to 7570 L (2000 gal). The UV clarifier is help to clear the green out of the water and to prevent nasty odors. This UL listed clarifier helps balance the pond and maintain clean water by using ultraviolet technology to reduce the need for chemicals and to improve water quality. The energy efficient 9 watt bulb lasts up to 8000 hours and should be changed every 12 months. This product is backed by a 1-year limited warranty.