The Aqua Flo 41407007 is a pH Booster quick change filter to replace the fourth stage of the QCRO and QCUF RO system. As the fourth stage of the RO system, the 41407007 pH Booster replaces the carbon poster filter remineralizes and raises the pH of water while also reduces chlorine, taste, and odor. Featuring a quick connect twist and lock design, the pH Booster filter is easy to change making service a snap and allowing the change over from the default carbon filter. To keep your system in top shape, change the Aqua Flo 41407007 every 6 to 12 months.