An Ultraviolet system uses UV to inactivate bacteria, viruses and cysts that may be in the water source that flows through the systems UV chamber. The effectiveness of Ultraviolet depends upon the dose of disinfectant received by the organism, which is the combination of UV intensity times the contact time involved. It is advisable to always pre-treat the water entering the UV system. Pretreating before Ultraviolet can be done effectively with our self cleaning 1 micron water filters.