Help with first regulator and CO2 tank

So i have a brand new regulator and I think I have it figured out. I can dial in the pressure just fine. there is another guage that is supposed to tell me how full the tank is instead of the pressure but it seems to be acting weird.

I have it hooked up to a 10lb CO2 tank that is supposed to be full and it registers 700. if i hooked it up to a 20lb CO2 tank that is supposed to be full it settles out at 500. this is at 38F.

Any ideas? Is my regulator guage defective?

The gauge is not defective. The gauge will not tell you how full it is, it will simply tell you the pressure in the bottle. At a lower temperature pressure will be less. At room temp it will read higher. The only way to tell how much liquid co2 is in the tank is by weight. Take the actual weight of the tank minus the TW (tare weight) of the tank. Until you have used up all the liquid in the tank it will not drop pressure. When it starts to drop you are just about completely empty. IMHO this gauge is almost useless for telling how much co2 is left.

Yeah, that’s been my experience with kegging and welding. Looks like you have half a tank for a month or two, then one day it’s empty

Good to know im not going crazy. thanks for the info guys.

Best case, that gauge is nothing but a literal 2 minute warning for kegging. In reality, it is not necessary because you really need some sort of spare for when it kicks anyway.