The Red Sea CO2 Pro System Deluxe is a complete, efficient and user-friendly system to maintain a desired level of CO2 in planted aquariums from 10 to 125 gallons (40 to 500 Liters). The Deluxe has everything included with Red Sea CO2 Pro System, and in addition it comes with the Solenoid Valve.The CO2 Pro System Includes:Full featured, dual gauge, safety Regulator that is supplied in versions suitable for connection to standard refillable CO2 cylinders and disposable CO2 cylindersIndependent, high precision, in-line, Needle Valve that can be located in a convenient location on the side of the aquarium and be set to stable flow rates as low as 4 bubbles per minute.Highly efficient CO2 Reactor 500 that includes an adjustable flow water pump and can dissolve over 180 bubbles of CO2 per minBubble Counter with integrated check valveReal time CO2 Indicator arrowSolenoid ValveDoes NOT come with CO2 bottle or tubingUser Manual (pdf format in new window)