Deionization

The Di filter goes after the RO membrane. A DI filter cartridge is filled with a black resin (note: the carbon block filter is white; the DI cartridge has black carbon-looking material). Once the RO membrane has removed most of the impurities, the DI filter cartridge removes the final impurities.

A color changing DI cartridge will change from black to brown as it is used. Once it is mostly brown, it should be replaced. A refillable DI resin cartridge can save you some money. One of our best selling Di cartridges is the Spectrapure Maxcap DI, which contains a high quality Spectrapure DI resin.