the ref has a tiny little brass one but that adjust the amount of co2 going into the tank. Yes the knob is the one on top of the cylinder it self. I have it turnned mid way on. The tiny one on the reg is just barely turnned on and my drop checker went into the green a cpl of hrs after the co2 came on and has stayed green all day.
thanks Kev I went on youtube and looked it up and saw just what your talking about. I think its pretty well set my drop checker went into the green not long after it came on this am and stayed green all day. I just didnt want anything to blow up lol.