A pressurized gas chlorinator is constructed in the form of a two-compartment pressurized container. The lower container is filled with a media liquid, such as hydrochloric acid (HCl). A pair of electrodes are located in the lower container beneath the surface of the media liquid, with one of the electrodes located at or near the bottom of the container and the other electrode located at or just below the top surface of the media liquid. Electric current is applied to the electrodes to cause a breakdown of the HCl into Hydrogen and Chlorine gas. A floor member is spaced a short distance above the surface of the media liquid in the lower compartment, and has an opening in it. This floor member comprises the bottom of the upper compartment; and gas is passed upwardly through the opening in the floor member into the upper compartment. Side walls surround the opening, and transport liquid (typically, water) flows into and out of the upper compartment around the side walls to absorb the gases, which are under pressure in the upper portion of the upper container. When the gas pressure drops, some of the transport liquid is permitted to pass over the top of the side walls to drop through the opening in the floor member to replenish the media liquid, which is constantly being depleted by means of the electrolysis action. This prevents excess gases from being present in either the lower chamber or the upper chamber.