In a pond, algae blooms, or ""green water"", can be a difficult issue to address safely and effectively. Not anymore! The Aquascape UltraKlear® UV Clarifier/Sterilizer uses a technologically-advanced T5 high output UVC bulb, making it more efficient than traditional UV clarifiers. The Aquascape UltraKlear® UV Clarifier/Sterilizer features a swirl sleeve that helps direct the water around the UV bulb, creating more contact time and increasing UV efficiency up to 50% over traditional UV clarifiers. Effectively clears unsightly green (pea soup) water algae blooms, Simple to use and easy to maintain, Features a swirl sleeve that optimizes UV efficiency, HIgh-output UV bulb maximizes performance, Easy-to-remove bulb and quartz sleeve, Can be mounted horizontally or vertically."