Please advise best effective zeolites (or salinity decrease substances) for decrease and adsorption of sodium, calcium, chloride and sulfate ions from limited amount of water.
Please read about different types of zeolite materials with their pore dimensions along with review articles in this area. It will help you to move further.
Zeolites have only cation-exchange properties, and moreover, they are mostly in Na-form. If you want to decrease content of cations (Na+, Ca2+) and anions ( chloride and sulfate) at the same time, zeolites are not fully effective, better is two-step process with cation-exchange resin in H-form and anion-exchange resin in OH-form.