The Aquaion Gas Chlorinator is a state-of-the-art, vacuum-operated, solution feed type which mounts directly on a chlorine cylinder valve. The chlorinator is mounted onto the chlorine cylinder valve using a very heavy-duty, positive yoke clamp connection. A chlorine gas flow meter panel indicates the amount of chlorine being fed and may be located wherever it Is safest and most convenient. Chlorine flow rate is manually adjusted and the design permits easy addition of a number of automatic flow rate control devices. A high efficiency, water operated ejector produces the vacuum necessary to operate the system. The ejector assembly contains a back-flow check valve system to prevent pressurized water from entering the chlorinator. A spring-opposed diaphragm vacuum regulator controls the chlorine gas flow rate and also acts as the safety shut-off valve.