The UV treatment is identically present in all UVION systems, because only a certain wavelength (254nm) of UV light reliably eliminates pathogens.First, the water flows through the UV chamber. The UV light immediately kills any bacteria, viruses, legionella and other pathogens that may be present in the water. The water is now germ-free. However, new pathogens are constantly entering the pool through bathers and from the environment. In addition, various algae grow in the water. The warmer the water, the faster algae and pathogens multiply. Therefore, the water now flows through a second treatment stage. The UV treatment is identically present in all UVION devices, because only a specific wavelength (254nm) of the UV light eliminates pathogens reliably.