Calcium helps your body function normally. A person gets essential amount of this element from water, so it cannot be removed completely. On the other hand, too much calcium makes water hard — this way, it can cause damage to household appliances. According to GOST, max. concentration of calcium in water varies from 30 to 140 mg/l.
If your tap water contains more calcium, you can install softeners, ion exchange filters, or reverse osmosis systems. They remove calcium salts and soften the water, while reverse osmosis filter, on top of that, enriches water with minerals. Before buying a filter, ask an expert for advise on a filter or on a package solution for water purification and mineralization.