Cations are necessary to cultivate any cell and they are added at low concentration. Macronutrients as the nitrogen, carbon, sulfur and phosphorus must be balanced according with the cell concentration required. The concentration that you mention (I guess that in  g/L) salt may be used. Consider the tolerance of the salt concentration for bacteria may be high due to the wall cell. At salt concentration very high, it will have inhibition because of the free water (water activity) is decreased, the cell transport is disrupted, the  is diminished.