Question: What does Deionization/Demineralization (DI) mean and what is its purpose?

Answer: Demineralization by Ion Exchange. DI is a mixed bed of resins which attract ions, salts or minerals and can entirely remove the metals and salts from your water. If your Reverse Osmosis system removes (95 – 98 %) of the minerals and salts, then you could follow it up with a D.I. cartridge or a D.I. in-line filter to remove almost 100 % of the TDS (Total Dissolved Solids), which would render your water with a TDS of near zero ppm. Your RO membrane rejection percentage will have a direct impact on the life of your DI cartridge or DI in-line filter. The DI will absorb everything in the water that is left behind by the RO membrane. Therefore, if your water usage requires a product with a zero (0) TDS, DI is the answer.