Track Biogas production?

I’ve been trying to find a way to track the amount of gas our Biogas digester produces… I’ve found a few very expensive laboratory type sensors… I wonder if anyone has come across some more affordable options or come up with something themselves?

Quite a few biogas digester setups bubble the gas through water to remove some impurities… I wonder if some kind of tipping counter and ball valves could be used to measure the water displaced… Clutching at straws here I guess :slight_smile: