Unique three stage blending cartridge provides softened/buffered/filtered water * Small amount of carbon filtered water bypasses softening resin to allow proper initial hardness. Buffering prevents water from becoming too acidic * Reduces hardness in water that can cause minerals to build-up in coffee and espresso equipment * Reduces minerals such as calcium and magnesium. Reduces chlorine, off tastes and odors * Sanitary cartridge replacement is simple, quick and clean. Internal filter parts are never exposed to handling or contamination