This is mixed bed and color changing Resin. Both cation and anion resins are combined in this one bag. Color changes as Resin is used up. We also offer bulk anion and bulk cation resins. This is enough for 4 refills of our refillable clear canister. Resintech MBD-30 is a self indicating mixed bed Resin. It is a mix of Nuclear grade hydrogen and hydroxide form resins. The anion Resin is a type I strongly basic gel Resin with an indicator dye that changes from blue to colorless as the resin exhausts. The cation component is a strong acid sulfonated Polystyrene gel type cation exchange resin. During exhaustion, as the indicator dye changes color, the appearance of the mixed bed changes from a Green color to a Violet color. Many manufacturing processes require high purity water for washing, rinsing and test purposes. Not all processes requiring demineralized water need the ultimate quality. However, they may require multi-mega ohm resistivity water. Resintech MBD-30 is designed to provide demineralized water with a resistivity in excess of 10 megohm. It is specially intended for use in cartridge applications with clear (see through) housings. Such systems are typically designed without meters and rely on the changing color of the mixed bed Resin to indicate exhaustion. In typical operation There is a safety line at the exit end of the cartridge, and when the color change reaches that level, The cartridge is considered exhausted and exchanged for a fresh cartridge. The actual quality that is obtained Depends on the manner in which the cartridge is configured. A constant supply of high purity water can be obtained by using two cartridges in series.