I guess what I am trying to find out is if the O2, oxygenating, aerating what ever you want to call it will remove more CO2 than what is injected.
It depends on a few factors. I'll try and explain the basics below.
In the image above the green circles represent CO2 molecules in our imaginary tank. The number of green circles on either side of the water surface wants to remain in equilibrium. The number of green circles that are dissolved into water depends on a few things but for explanations sake let’s assume an equal ratio even though that’s not real life. Therefore, the image above is said to be in equilibrium.
If we inject more green circles into the water like the image above then the circles will want to leave the water since we have a lot more in the water. Remember, these gases want to stay in equilibrium.
Notice in the second image there are less circles near the surface? The molecules are closer to the surface so it’s easier for them to “pop out” into the air. Is there anything you can think of to increase that rate?
What if we made the water surface larger, the tank depth more shallow or pumped the molecules closer to the surface. That would increase the rate of green circles leaving the water correct?
Increasing surface agitation moves molecules closer to the surface allowing them to leave quicker than no water current. If we trickled water over a huge surface area, such as a wet/dry filter, this would allow more molecules to leave the water because we have a much larger surface to air percentage.
These are some of the factors that will influence how much CO2 we have in the water. If we increase surface agitation or surface area we lose CO2. However, carbon dioxide molecules are not the only ones we deal with. The oxygen molecules will also follow these same principles.
If we have fish “eating” oxygen molecules in the water they eventually become depleted causing the fish to suffocate and die. So we provide water movement or other means to bring oxygen molecules back into the water. These principles work both ways. Remember the gas(s) wants to remain in equilibrium.
Do you see why CO2 and Oxygen are independent now? What about the balance of CO2 injection rate and water movement? That is a VERY brief explanation of the laws I posted earlier and how they can affect what we are trying to do.