UV Clarifiers are designed to destroy the ultra fine planktonic algae that cause green water. When algae cells are exposed to the bulb’s ultraviolet rays, the radiation destroys the cellular wall of the planktonic algae. As a result, the tiny particles of dead algae clump together and are removed by your mechanical filtration system.
UV clarifiers are a great addition to a pond suffering from green water caused by full sun exposure or too many fish. Please note, UV Clarifiers do not affect string algae.
Be sure to pay attention to the flow rates listed on each particular UV filter. If your pump’s flow rate is higher than recommended, algae will not be exposed to the UV radiation long enough to damage the cell. Thus, rendering the UV filter virtually useless. By using a pump that is too large, you also run the risk of damaging the UV unit by creating too much pressure. If your pump is too small, you run the risk of the UV clarifier acting like a sterilizer. With slowly moving water, the UV bulb will kill both the algae and any beneficial bacteria that floats by.
While a UV clarifier can work wonders on your water garden it is only a patch to the real issue. Make sure you are properly maintaining your pond, using an adequate amount of filtration, keeping a low fish population, and utilizing your bacteria products.