Colombo: Just one more thing.
If Jose, T.Barr or anyone else is saying that CO2 mist is better for plant growth, how do you measure it's concentration? How can you be sure that 30 ppm CO2 in fully dissolved form is the same as 30 ppm CO2 in gas form?
If I paraphrase it, you say that if we have two tanks with the same conditions (same volume, same substrate, same plants, same nutrients level ... with only difference being CO2 form), and in the first one we have CO2 mist (in gas form) while in the second one we have fully dissolved CO2 (in aquatic form), then the plants will grow faster/better in the first tank. My question is, how do you measure the mist CO2 concentration? Do you have any special mist CO2 meter for it? Or how do you know that you have the same concentration of CO2 in both tanks? The only CO2 we are able to measure is the one in fully dissolved (= gas) form. If CO2 is not dissolved yet, we are not able to measure it. Do you get my point? So if it would be true that CO2 mist is better for plants then it would mean that they get much more higher CO2 concentration than is the concentration of fully dissolved CO2 in water. And if this is true, then you don't have same conditions in both tanks, so your comparisson is not valid.
Maybe CO2 mist is more effective way of CO2 supply (you supply smaller amount of CO2 gas into your tank to get high CO2 concentration), but if you ensure the same high CO2 concentration in fully dissolved form, the plants may grow just as fast. So again, if you want to compare the plant growth rate using CO2 mist vs. fully dissolved CO2, then you have to ensure the same concentration of both forms in your tank. But there is no way to measure the CO2 mist concentration as all CO2 meters are able to measure just the fully dissolved CO2.
Lets see Ardjuna, to see the difference between the two forms you only need to inject exactly the same ammount of co2 into the tank. One time dissolve it all and the next time use an atomizer of some sort. The BPS are kept the same so whatever difference you see should be due to the different co2 forms in water because the total co2 injected is the same. So you dont need fancy co2 measuring kits here only a bubble counter. You dont measure the dissolved co2 because as you say this is not measuring the bubbles. This is clearly explained in the link I added.
There are more questions to be answered like:
1) How do plants grow with only co2 bubbles and the least dissolved co2 possible like in ADA tanks?
2) Has the size of the bubbles got any effect?
3) Probably co2 bubbles have less an impact at higher co2 ppm
Toms Barrs experiments show mostly a middle ground where you dissolve quite a lot of co2 but still have micro bubbles.
I like these kinds of conversations even if they look crazy to hobbyists because I think this is where you learn the most.
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