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it is an on-demand process that supplies large amounts of highly purified water as needed. Deionization removes total dissolved solids (TDS) from water using ion exchange resins, controlling the electric charge of ions in the water to remove the TDS.

Deionization is the removal of the charged molecules or ions or atoms from a liquid. Deionization of the water takes place by passing it through two resins which help in removing the negatively charged chlorine ions and the positively charged sodium ions.



The cationic (negative) and the anionic (positive) resins are used in the deionization process.

The anionic resins are made up of positively charged ammonium groups which are precharged with the hydroxide ions. Anionic resins help in attracting the negatively charged ions like chloride, fluoride, sulphate etc to release an equal amount of hydroxide.

Sulfonic group (negatively charged) which are precharged with hydrogen ions make up for the cationic resin. The cationic resin helps in attracting the positively charged ions like magnesium, calcium, sodium etc in the water to release an equal amount of hydrogen ions.

Hydrogen and the hydroxide interact with each other, leading to the formation of water.


  • Deionization is a cost-effective and very convenient method for filtration of water which produces extremely purified water for aquariums and hydroponic uses.
  • Deionization helps in removing all the ionised minerals including the organic and inorganic salts from the water by the process of ion exchange.
  • Deionization leads to the production of high-quality water which has the purity of distilled water.
  • When compared to distillation, deionization saves the cost, is fast and uses less energy.
  • It can be used to produce the very large amount of purified water as and when needed.
  • The process of deionization can eradicate the total dissolved solids or TDS from the water by using the ion exchange resins and controlling the electrical charge of the ions in the water.
  • The resins of deionization attract the non-water ions and place the water ions at their place and thereby produce much-purified Basically, it works like a magnet which attracts the charge towards itself.
  • Deionised water can help in the prevention of corrosion.



The colour changing mixed bed type is the best deionization resin for usage. It changes its colour from bluish green to amber when the resin is finished. The deionization filter cartridge is opaque for visibility and for being able to replace it conveniently.

It is important to note that the cartridges should be changed every 12 months or every 3000 gallons later- whichever is sooner- so that you can extend the life of the deionization resin.