Gas-exchange experiments

[PeerUnk]

All electronics parts for my own sensor build are delivered except the O2 sensor. Software is up and running, hopefully I can actually do some tests next week. Fingers crossed 🤞

 

[hax47]

Hi, nice discovery and good to be aware of. How did you add the CO2? With a soda bottle I guess looking at the sudden spike? What ratio (Volume addition and tank) did you add? The amount of oxygen (or absence?) in the soda bottle might affect your oxygen reading as well…? The sensor actually reads o2 percentage right?

Yes, with soda. Typically soda water contains about 5-8 g/l CO2, so 100x dilution gets you to 50-80 mg/l range. For me, 900 ml SodaStream bottle brings the CO2 in the 120 l tank (~100 l water) to about 45 ppm.

Your finding in my own words: a lot of co2 is added to the water. This will equilibriate with the trapped and measured air. Because co2 will increase in the air and it’s co2 reading. The percentage o2 is affected and will read lower, even the amount of oxygen in the trapped air and water is the same.

Something like that, the amount of oxygen in the water is the same. In the air, the total amount of gas molecules remain, but the relative fractions will be the same as in the water. But since the air pressure remains, the total oxygen in the air will be less.