IUnknown, looks like a brilliant idea! We were all looking at the pieces, but you put the two critical ones together! Excellent.
So to be real clear, the advantage here is removing KH uncertainty out of the quest for knowing the CO2 ppm in our tanks, right? If so this is great.
I can see the need for one of those nice little sphincter valves here. But a fw questions:
1) Do we know that gaseous CO2 is as soluable into the chemicals used as reference solution?
2) If we assume that is is equally soluble into this chemical as it is in water, does this process (and the drop checker) work due to there being equality of co2 concentrations in the two fluids (tank and solution)? Of is it just the the solution's CO2 concentration moves in reference to the tank, just not to the same degree?
3) Do you know if that reference solution is harmful if it accidently spills into the tank?
Good thinking though!