To obtain pure hydrogen from the tank, heat is added and the pressure in the tank is allowed to drop. This causes the hydrogen to separate from the hydride molecule and flow out of the tank. During this operating mode, tank pressure falls to less than 500 PSI. The molecule is thus returned to its original condition as an alloy and the process can then be repeated. When all the hydrogen has been removed from the tank the pressure will fall to 0 PSI.