DM or deionized water is simply water that has had most of the mineral content and dissolved ion content removed. It is just pure water. The cleanliness of the water is rated as its resistance value. It should be noted that pure water will not conduct electricity. It’s the ions in the water that conduct the electricity. Deionization is simply an ion-exchange process in which water flows through resin beds or resin beads. Cation resin exchanges hydrogen ions (H ) for positive ions, and anion resin exchanges hydroxide ions (OH-) for negative ions. Sometimes there are two column of Deionization – one for the Anions and one for the Cations, but the highest quality water is produced by what is called mixed-bed DI or “MBDI” whereby the Cation exchange and Anion exchange resins are mixed together. Separate Anion and Cation columns are now used infrequently because of the superiority and economy of reverse osmosis. Deionized water quality is measured by conductivity or resistivity. In the chart below, resistivity is represented above the line in ohms or megohms and conductivity is below the line measured in microsiemens.

Deionized (or “DM”) high purity water is an essential ingredient in hundreds of applications such as:

• Medical offices
• Laboratories
• Pharmaceutical companies
• Cosmetics companies
• Large aquariums,fish tanks,and reefkeeping facilities
• Electronics manufacturing plants
• Food processing plants
• Plating and anodizing
• Final rinse at car wash!