Save money by refilling your own DI resin cartridge!  This resin is available in four sizes.  Resin changes from purple to a light tan color when exhausted.  The color change is visibly obvious. The 8.72 lb refill is enough resin for a approximate six refills of a 10" x 2.5" cartridge, or one refill of a 20" x 4.5" cartridge.