Cal Pump is a well established, reputable manufacturer that has been producing quality garden pond equipment including UVC sterilizers since 1958.
The Cal Pump UV Clarifier range is designed for use in most backyard fish ponds to 6,000 gallons. The Cal Pump UV bombards the floating algae as it passed through the UVC sterilizer unit, bleaching the algae's DNA/RNA using UVC rays, causing the dead algae to clump together, making it easy for your pond filter to remove.
Most pondkeepers know that the best way to ensure clear pond water is with an ultraviolet sterilizer. Some often overlooked factors are what to do when the UV light is not doing the job anymore. Usually, this is a simple as an old lamp. Depending on the brand, UV lamps should generally be replaced about every 12-15 months of use.