The Glacier Clear Water Purification System is a unique, two stage, mainline system. (patent pending). What this means to you, is that your entire house is supplied through the same system, often eliminating the need for water softeners. With the two stage system, a pre-filter removes floating particles (fecal material, turbidity, asbestos etc.) while a second exclusive silver impregnated granular activated carbon filter (patent pending) effectively reduces bacteria growth and other dangerous contaminents such as P.C.B.'s, dioxins and other poisonous chemicals. more... See more text