HALO UV sterilization systems use ultraviolet light to disinfect water continuously without chemicals, making them an environmentally friendly alternative to chlorine that produces no disinfection byproducts and operates 24/7 with low electrical needs. UV is FDA-approved and more effective than chlorine or chloramines, though it only eliminates microorganisms and must be combined with other filtration methods to remove contaminants like heavy metals, salts, or chemicals. The system requires three main replacement parts: the UV lamp, quartz sleeve, and ballast for ongoing operation.