Automatic De- Ionizer comprising five sub-systems for removing ionic contaminants from various liquids at low energy consumption is devised. Based on the charging-discharging principle of capacitors, the deionizer conducts deionization through applying a low DC voltage to its electrodes for adsorbing ions. This ionizer is very effective and economical too. Automatic De- Ionizeris part of a multiple-process treatment system that produces high-quality water required for specialized applications. Choose from a flexible configuration of weak-base or strong-base resin tanks.At the mean time of discharge, surface of the electrodes is regenerated on site and reset for performing many more cycles of deionization-regeneration till the desirable purification is attained.