Clarifier suitable for small ponds up to 3000 gallons using pumps up to 1800 gph. Fully submersible unit's vortex flow design exposes water longer to ultraviolet light. Two glowing monitor halo rings, visible from any angle immediately shows it's working. Comes complete with 9000 hour-long life 20 watt lamp and water tight quartz sleeve Includes transformer and 18' grounded power cord. Black color is unobtrusive whether used in or out of the water.