UV-C light is germicidal and operates most efficiently at a wavelength of 250 – 260 nanometres. It has a photolytic effect whereby the radiation destroys or inactivates the microorganism so that it can no longer multiply. Unlike other techniques, UV-C photolysis rarely produces potentially dangerous by-products. The actual lamp is housed in a quartz sleeve. This sleeve not only helps maintain maximum operating temperature, but also prevents the lamp from coming in contact with the water. Disinfecting water with UV technology does not change the chemical properties of the water and also eliminates the chance of overdosing.