I'd get one of the following Victor dual stage chrome plated medical grade regulators and add a solenoid and an Ideal metering valve. I have 5 of the Victor regulators. The Victor regulators and the Ideal metering valves are a great combination! I have 2 of the SMS 122 controllers and I haven't had any trouble with them.
http://shop.ebay.com/merchant/mrmoto...Q_fromZQQ_mdoZ
This is the regulator that ColeMan mentions.
http://www.greenleafaquariums.com/co2-regulators.html
Orlando has complete systems too. He doesn't have the price of a complete system using the "Ideal Regulator" listed. Soon, he will have 10# cylinders in his line.
http://www.greenleafaquariums.com/co2-systems.html
SuMo has a very good line of regulators too.
http://www.sumoregulator.com/
Rex Grigg does too.
http://www.bestaquariumregulator.com/index.htm
Victor dual stage regulator
Ideal metering valve
