argon pressure

Hi,every tigger
I am new 250ex owner.I have a question about regulator pressure.
Is the pressure supposed to return to zero within around 10 seconds after I turn off the valve of the argon bottle?
If it is abnormal to return to zero right away, does it mean that somewhere is leaking?

No, the pressure should stay up for longer than that. Check your points where the hose clamps attach and retighten them.

Use some soapy water and check for leaks around the regulator where the gauge screws in.