Is a secondary, electrogenic Na(+)/H(+) antiporter that catalyzes Na(+) uptake and proton efflux. Makes modest contributions to pH homeostasis in the alkaline range of pH but is not contributor to Na(+) resistance. Appears to have a repressive effect on growth and on alkaline phosphatases production in the presence of sodium, by affecting the transcription of the phoP/phoR two-component regulatory system. The antiport activity is markedly inhibited by both valinomycin and CCCP, and modestly by nigericin. Belongs to the NhaC Na(+)/H(+) (TC 2.A.35) antiporter family.