First, the calibration of the osmostat has been handled using the Widom insertion technique requiring alchemical work extracted from proposed NCMC moves where water molecules are alchemically transformed to an electrolyte unit. Our method is straightforward to implement, at the expense of a slightly higher error on the computed alchemical potential compared to the algorithm of Ross and co-workers. Then, we calculated solvation free energy of water by decoupling Lennard-Jones and electrostatic interactions during insertion of water molecules in the bulk using NCMC moves. Previous chemical potential for inserting a single electrolyte unit in bulk water by alchemical transformation is used to grasp thermodynamics of electrolyte solvation at infinite dilution. Our value of water solvation free energy as well as electrolyte solvation free energies are in good agreement with the literature, demonstrating that NCMC move is a versatile tool that can be used for both alchemical transormation and particle insertion in dense fluid. Finally, the MC moves for inserting/removing an electrolyte unit are similar to those of Ross and co-workers and show that our implementation of the osmostat yields the correct electrolyte concentration in system initialized with pure bulk water.