CO2 mist figured out

Tom Barr

Staff member
Jan 23, 2005

You should see a dramatic difference in a day, not a week if it's properly set up.

It'll take a little more tweaking to get the good diffuser disc rate going, but once done, you should see the dramatic growth.

Scapers........well, they need good growth too and better growth will make their lives easier and achieve the look they are after sooner.

Algae, well, this needs no comment, we all see the utility here.

Dissolved versus undissolved bubbles.............this is where folks are getting boondoggled.

Yep, you are.

The initial few minutes/hour/s(typically 1 to 3 hours after the light/CO2 comes on) are mainly dissolving the CO2 into solution.

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?

You are adding CO2 to a solution that is already super saturated.
After 1-2 hours, the micro bubbles will persist and float around the tank.

This is true for my venturi reactors.
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, the flame test was not conclusive.

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!!!!!!!!!!!!!!!!!!!!!!!!

So this means, and I know I'm right(rare), that the CO2 dissolving is greatly reduced later at a styable 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, 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.

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.

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. there.

I finally figure out why that dang little venturi diffuser worked so good, only took me 12 years ! haha

Tom Barr