You have that problem only if you decide to remove all the salt. You could decide to remove say 20% of the water and make that only H2O; effectively getting H20

You have that problem only if you decide to remove all the salt. You could decide to remove say 20% of the water and make that only H2O; effectively getting H20 and a higher concentration of salt water as outcomes. I say this having recently read about the desalination plant in Dubai.