If you have a RODI system, you will eventually have to change the DI resin since it will become depleted as water runs through it. Deionization Resin is simply a mixture of cation and anion resins that will attract and attach to other contaminants that may still be in your water after the RO membrane. Changing the DI resin is super easy, and in today’s video, we give a few quick tips on how we pack our refillable DI cartridges. The biggest key for a long lasting DI stage is to pack the cartridge as tight as possible. If the resin is not packed tightly, water can eventually channel through it not allowing it to contact the remaining active beads of resin.