Ubulukhuni bamanzi ikakhulu buqulunqwe zii-cations: calcium (Ca2+) magnesium (Mg2+) ion.Xa amanzi akrwada aqulethe ubulukhuni edlula kucwecwe lwentlaka ye-exchanger, i-calcium kunye ne-magnesium ion emanzini zibhengezwa yintlaka, kwaye ii-ion zesodium ziphuma ngaxeshanye.
Ngale ndlela, amanzi aphuma kwi-exchanger athambekisiwe ngamanzi kunye nee-ion zobunzima zisusiwe.Xa i-resin ibhengeza i-calcium kunye ne-magnesium ions.