Help needed with Carbon Doser

[Gtinnel]

I’m trying to setup my first calcium reactor and I am having a problem with my Carbon Doser. Its the older Carbon Doser and from what I read when I initially hook it to the co2 tank I need to have the knob on the front turned completely counter clockwise which lowers the working pressure down to 0. Then once it’s hooked up and the tank valve is on, turn the knob clockwise until the pressure gets to around 10psi.
The problem is when I turn the knob counter clockwise it gets loose enough that I think I am actually going to unthread the knob completely. I expected it to turn so far and then stop but it doesn’t feel like it’s going to stop.
I turned it to where it felt incredibly loose and quickly opened and shut the valve on the tank. The pressure went to over 20 psi and gas was quickly coming out of the 1/4 outlet line. Worried that the pressure was too high and could damage the Carbon Doser I quickly disconnected the regulator from the tank.

Do I just need to keep turning the knob on the front counter clockwise even though it feels like I’m going to completely thread it out and if so will it eventually stop turning? Was the gas quickly going out of the tubing because the pressure was too high? Was that pressure enough to damage the Carbon Doser? I did get this Carbon Doser for a suspiciously cheap price.

 

[backbayreef]

It should be around 12-15 psi but regardless, you should slowly adjust the number of bubbles per second. Start slow

Effluent: mine runs almost like a stream and adjust the CO2.

Test alk regular and increase/decrease CO2 based on that. Just change one thing at a time.

 

[Gtinnel]

My problem is with me turning the knob as far counter clockwise as I felt comfortable it was already over 20psi. This could just be a problem with me not being willing to turn the knob far enough. At that pressure even with no power to the carbon doser co2 was quickly coming out of the outlet tube.

 

[Gtinnel]

Ok so apparently I was just too timid with turning the knob. If you turn it completely counter clockwise it releases the spring tension and is incredibly loose but it is captive and can’t come completely out.
I am now able to easily adjust the pressure with the knob but it is still leaking through with the carbon doser unplugged.

I think I know why it was so cheap.