The selective exchanger is a strongly basic anion exchanger resin, which is used for nitrate or nitrite removal from drinking water. It functions as a macroporous (pores >50nm) anion exchange resin in chloride form (Cl-) and is heterodisperse non-uniform particle size). The anion exchange resin is approved for use in food and drinking water applications. The nitrate can also be safely removed at moderate to high concentrations of sulphate without displacement of already adsorbed sulphate. The resin is easily and effectively regenerated with commercially available regenerating salt tablets (common salt).