IONTEC softens or demineralizes water used for beverages or for other purposes (e. g. for heating, cooling, cleaning).

For ion exchange there are ion exchange resins in the unit. They contain loosely held cations or anions. These ions exchange with the ions in the treated water as it passes through the unit. For softening of water a resin containing Na⁺ is applied. The Ca⁺⁺ and Mg⁺⁺ ions which form hardness in water are exchanged for the Na⁺ ions of the resin. When most of the ions in the resin have been replaced the resin is exhausted and a regeneration cycle is initiated.

Regeneration with brine strips out Ca⁺⁺ and Mg⁺⁺ from the exhausted resin. For water demineralization all dissolved ions are removed from the water. Therefore, the water passes through a cation resin containing H⁺ to replace all cations and through an anion resin containing OH^- to replace all anions. H⁺ and OH^- then combine and form purified water.

Both resins can be in separate vessels or together in a single vessel (mixed bed design).