Pondlife Turbo-Twist U.V. Pond Clarifiers are the most efficient devices for clarifying ponds on the market today. They feature a quartz glass sleeve with a compact fluorescent high-output, PL-Type UV-C lamp surrounded by a revolutionary "Turbo-Twist" flow design to increase dwell time, which in turn increases efficiency. Continuous ultraviolet sterilization of pond water helps eliminate algal blooms for crystal- clear water. It eradicates most harmful micro-organisms on the initial pass through the chamber. Its triple-treatment time fully utilizes all the available U.V. output of the lamp and ensures that disease-causing pathogens cannot reproduce, thus decreasing the possibility of a disease outbreak in your system. Pondlife Turbo-Twist U.V. Pond Clarifiers are designed for use in all pond systems. Pond Turbo-Twist 3 x 9 watt, treats up to 2,000 gallons of pond water. 500 gph.