The output will be exactly the same regardless of the length of the hose until the pressure needed to maintain the volume is exceeded and then the machine will simply shut off (no gas production).
Output volume is independent of pressure. Pressure rises as resistance to flow increases (depth of water, kinks in hose, length of hose, etc.). The machine is limited (for safety) to 2.5 psi maximum pressure. But all during this time, the output volume stays the same.
You can test gas volume at home as per:
How do I measure Brown’s Gas Production?
Do I need to make an elaborate volume test apparatus like you show in ER_VolumeTestApparatus.doc in order to measure gas production? No, that’s overkill for what you need. The VTA allows you to take reasonably accurate measurements without assistance. You can get reasonably accurate gas volume by timing the filling of a pop bottle … Continue reading
But (assuming you have no gas leaks) if you have gas at the end of your hose and the machine hasn’t shut off, you are getting the same gas volume as at the beginning of the hose.
The difference is that the machine’s pressure has risen to force the gas past the resistance.
So the gas output always remains the same.