I would imagine, for testing purposes, that the "Breather Bags" that people use to ship fish in would work for a membrane--The Bag--let's C02 Out--Oxygen In. Reversed (into/toward the Drop checker): its should let the C02 In. But will it let it back Out to maintain equilibrium? Hmmmmmmmm.....For those who don't read many other aquatic plant forums, Tom Barr did some experimenting with this device and came up with the idea that you could get rid of the air gap entirely, and speed up the response rate considerably, just by using a gas permeable membrane to hold the reference KH solution. Then, if that membrane is in the form of a stocking over the business end of a pH probe, you have a CO2 probe - with fast reaction and great accuracy. He has done a prototype, of sorts, and it works. And, he is working towards getting this available for all of us.
Needing one clarification: Drop Checker fluid--set to Kh 5 will read the same C02 ppm as what is in the Tank? Meaning regardless of tank Kh (2, 6, 8, 12 whatever) the ppm of C02 in the tank will match the Kh4 Soultion? I can almost grasp that, but it just doesn't seem right....... I looked at the "Table" posted:
And I'm just missing something. I'll re-read that a couple dozen more times and see if I can get it to "Click"........:rofl: