Ultraviolet Clarifiers are a proven method of controlling waterborne planktonic algae and other harmful pathogens associated with aquatic recirculating systems, such as ponds, when and if it is used correctly. It, unlike other possible remedies, such as ozone or chemicals, has no residual life in the pond and is harmless to everything that does not get direct and close exposure to the radiation that they emit.
It is important to remember that the UV energy must hit the targeted organisms to be effective. The first hurdle is the bulb glass itself. It can be less expensive soft glass or higher quality hard quartz glass. The quartz sleeve and the transmission rate through the quartz sleeve can also vary a great deal, and again, that depends on the quality of quartz used. Higher quality generally means higher transmission rates, higher efficiency, but higher acquisition cost in both cases