Salinity disturbs both apoplastic and cytosolic Ca2+ and pH ([Ca2+](apo), [Ca2+](cyt), pH(apo) and pH(cyt)) homeostasis, and decreases plant growth. Seedlings of Vicia faba L. cv. Fuego were cultivated in hydroponics for 7 days under control, salinity (S), extra Ca (Ca) or salinity with extra Ca (S+Ca) conditions. The [Ca2+](apo), and pH(apo) in the leaves were then recorded in parallel by a pseudoratiometric method, described here for the first time. Lower [Ca2+](apo) and higher pH(apo) were obtained under salinity, whereas extra Ca supply increased the [Ca2+](apo) and acidified the pH(apo). Moreover, the ratiometric imaging recorded that [Ca2+](cyt) and pH(cyt) were highest in S+Ca plants and lowest in control plants. After all pretreatments, direct addition of NaC6H11O7 to leaves induced a decrease in [Ca2+](apo) in control and S+Ca plants, but not in S and Ca plants, and only slightly affected pH(apo). Addition of NaCl increased [Ca2+](cyt) in protoplasts from all plants but only transiently in protoplasts from S+Ca plants. Addition of NaCl decreased pH(cyt) in protoplasts from Ca-pretreated plants. We conclude that Ca supply improves both apoplastic and cytosolic ion homeostasis. In addition, NaC6H11O7 probably causes transport of Ca from the apoplast into the cytosol, thereby leading to a higher resting [Ca2+](cyt).