what are the examles of deionization

The removal of ions from a substance making it mineral free.

tank needs to be changed

you can reduce TDS by reverse osmosis method, deionization method or distillation method or by using activated charcoal.

Distilled (or double-distilled water; DDH2O) removes all but pure water molecules from a portion of water for use in the laboratory. While other treatments may have similar effects as distilling, they can leave more traces of impurities in the water or only act on a certain portion of the treatment of water (like removing ions, with deionization. reverse-osmosis, can be combined with other treatments to give nearly the same thing as distillation yields. Such purification methods might be deionization, ozonation, filtration and irradiation.