Media cartridge with linear, adjustable bypass

An ion exchange resin cartridge comprising:

• An inlet in fluid communication with a feed chamber and an outlet in fluid communication with a mixing compartment;
• A media compartment containing one or more ion-exchange resins;
• A bypass port in fluid communication with the feed chamber and the mixing compartment;
• and
• A bypass regulator that is adjustable by linear movement, said bypass regulator comprising a valve;
• Wherein the mixing compartment comprises an insert therein that is in fluid communication with the media compartment and the bypass port, the insert comprising the bypass regulator, the bypass port, a filter element in a filter element cover, a first end cap of the filter element affixed thereto, an end cap sleeve, and an elastic device;
• Wherein a first fluid path is defined by the feed chamber and the media compartment such that fluid flowing through the first fluid path contacts the one or more ion-exchange resins to form a treated fluid that enters the mixing compartment;
• and a second fluid path is defined by the feed chamber and the bypass port such that fluid flowing through the second fluid path does not contact the one or more ion-exchange resins and is untreated upon entry into the mixing compartment.