In this work, we proposed a variant of the osmostat implementation that we implemented in RASPA, a software dedicated to simulation of adsorption in porous materials. Our ultimate goal would be to employ in the future our osmostat version for the study of various electrolyte insertion in porous materials in equilibrium with a saline reservoir. The paper is organized as follows. First, we proposed another version of chemical potential calibration in the semigrand canonical ensemble (∆µ, N, V, T ) by using the Widom insertion technique with NCMC move to transform alchemically water into an electrolyte unit. Then, in order to assess the accuracy of our chemical potential calibration, NCMC move is used to study thermodynamics of electrolyte solvation at infinite dilution by calculating the free energy of water solvation with our modified Widom method. Finally, the chemical potential is used as the thermodynamic parameter governing the osmostat to gradually perturb bulk water that transition into an electrolyte that reaches concentration dictated by the previously calibrated chemical potential.