In experiments, NaCl electrolyte at concentration of 2 M penetrates chabazite when only 7 water molecules per cell are adsorbed which is lower than loading of 14 water molecules obtained by GCMC simulations (Figure ). Therein, we calculated the alchemical work required to solvate a single NaCl pair in zeosils at different water loadings. The results are reported in Figure and reveal a lower alchemical work, associated with a worst solvation of the ions due to the low amount of water presents in the zeosils. On the contrary, at very high amount of water molecules the alchemical work also diminishes for faujasite and chabazite because the dense fluid in cages cannot accommodate easily the intruded ions.