KoiPondFever.com offers top brand UV sterilizers and UV clarifiers for pond algae control as well controlling parasites, protozoans, and bacteria. To start lets define the difference between UV clarifier and UV sterilizer. These two different terms has to do with what you are trying to control. UV clarification means that you are controlling free floating algae that turns the water green and murky. Free floating algae robs the water of oxygen and creates wide ph fluctuations from day time to night time. The UV light destroys the cells of free floating algae causing it to die. It generally takes less UV light to kill free floating algae in the koi pond than UV Sterilization. UV sterilizer is the term used to control viruses, bacteria, and protozoa. In general, larger organisms, such as protozoa, require a higher dose of UV radiation than smaller organisms, such as bacteria. In a koi pond environment the same unit does both. It just takes more UV radiation to sterilize than it does to clarify. The practical use of UV sterilization would be in a quarantine tank or pond to prevent spread of disease from one fish to another through the water. Aqua Ultraviolet UV Sterilizers are rated by pond size for both clarification (Koi Pond Algae Control) and sterilization (Koi Pond Bacteria, Parasite, and Protozoa Control).