[APD] CO2 mist and the persistence of the micro bubble

[Thomas Barr <tcbiii at yahoo_com>]

Comments,

Dissolved versus undissolved bubbles.............this is where folks are getting boondoggled.
There is a two step process.
 
1.The initial few minutes/hour/s(typically 1 to 3 hours after the light/CO2 comes on) are mainly dissolving the CO2 into solution. 
 
2.Once a high level builds up, then it becomes much more difficult for the CO2 mist to be dissolved. Chemically: it is more difficult to dissolve a substance against an increasingly larger concentrational gradient.
 
So in the AM when the lights first come on, the CO2 is poor and the gas rapidly dissolves entirely. 
 
Say we get up to 30ppm dissolved in one hour.
Great, plants are bathed in a rich CO2 solution.
Still the same and works well as what was previously discussed for the last 40 years.
 
Now, what about the CO2 bubbles at 30ppm?

Are they so quick to dissolve at this level of CO2?
 
You are adding CO2 to a solution that is already heavily super saturated.
The O2 is at best only mildly super staurated.
 
After 1-2 hours, the micro bubbles will persist and float around the tank.
This is true for my venturi reactors as well.
That gas build up in the external reactor tubes as well as the internal venrturis are similar later in the day.Think about what that gas might be, I'd suggested it was O2 at one point, the flame test was not conclusive(it put the flame out, suggesting CO2, not O2). 
 
I could see the external reactors perhaps building up O2 later in the day, but what about the internal venturi reactors?
 
No way, there's nothing to degas O2 in there! This rules out the O2 theory. No other gases are super saturated, thus unable to increase and degas of solution, only O2 and CO2, and CO2 is much higher than O2 relative to ambient in all cases, so this makes sense chemically regarding concentration.   
 
So this means, and I know I'm right(rare), that the CO2 dissolving is greatly reduced later at a stable given CO2 dosing rate in the day after you build up to a certain level. What level? I'd guess about 30ppm.
 
After you get this into the tank( 30ppm dissolved CO2), then this CO2 micro bubble theory starts to work. You still have 30ppm in the tank, but now you have added pulse of pure CO2 mist on top of that for the plants.
 
It is not one _or_ the other, they are synergistic, one complement and builds on the other.
My mistake in the past was assuming that the gas in the tube was O2, it's not, it's CO2 excess that's much more difficult to dissolve.
 
Thinking about the internal venturi reactors has shown that it cannot be O2(why would it degas there just like in the external sealed tubes)?
 
I tried this without any plants(thus no O2 build up), I had gas build up later in the day, thus reduction in CO2 dissolving at higher ppm levels.
............so there.
I finally figure out why that dang little venturi diffuser worked so good, only took me 12 years ! haha
 
By using comparative diffusers, reactors etc, I was able to muddle through this.
One by itself would not have answered this question.
 
30ppm bathes the entire plant, the mist of relatively pure CO2 bathes part of the plant.
Together both drive photosynthesis at a rapid rate that I've observed.
 
Regards, 
Tom Barr
 
www.BarrReport.com  This month's very in depth K+ review article completed.



		
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