CO2 dual stage regulator output pressure fluctuates

[Martin]

Is it normal for a dual stage CO2 regulator to have the second stage fluctuate a bit? The pressure for the second stage is around 30 to 40 psi, and I reduce the flow some more with the needle valve before the bubble counter. Over around 15 to 20 seconds the pressure slowly goes down by around 5 psi, then it relatively quickly (around 1 second) goes back up by 5 psi, and the cycle continues. I can also see the pressure change by the speed of the bubble counter. Over time the maximum pressure doesn't change, it always goes back up to the same PSI, but I'm a bit concerned about it fluctuating. It's an Aquatek regulator. Is this normal?

[charlie]

Don't think it is normal, I would suspect regulator is defective.
One thing you can do is check the entire set up for a leak.