Air Bubbles and plants

[Sonny Disposition]

OK. Plants like philodenron and pothos growing with roots in the tank absorb more nitrogenous waste than an equal quantity of submersed plants because leaves exposed to the air can take advantage of atmospheric carbon dioxide.

Since CO2 is present in the air, could you expect to get better growth of submerged plants by bubbling air into the water with an airstone than you could, say with a htb filter?

Or does water absorb oxygen at a greater rate than it does CO2?

[ingg]

Interesting question!

If I understand the mechanics correctly, a typical airstone and a hob filter do the same thing - break surface tension. Thus, same resulting o2 and co2 levels from either... I think.

I wonder though if you did a mist/powered diffusor on the air supply though, as that may keep surface tension?

[eleontie]

With an airstone or surface agitation you would get CO2 concentrations closer to the atmospheric air, for plants that is better than almost no CO2 ( what would happen if you get very little surface circulation, many plants and high light ). When you inject CO2 you do not want that agitation because you try to keep the carbonic concentration in the water higher than in the air.

Bubbles in the water are still air surface . Finer the bubbles , greater the surface. So... Dave, no you would make the things worse.

Eugen

[Sonny Disposition]

Thanks, guys. I knew I would get good answers from this list.

[ingg]

I think I would disagree on the last part of that eugen.

Fine enough bubbles would not pop at the surfacr. As atmospheric air has more co2 than a water column...wonder. If we could test this somehow!

If you say set an air supply into an active reactor.... Got some noodling to do, this has piqued the interest of the engineering geek in me.

[ingg]

I read up a bit more.

Atmospheric ppm is a lot higher - 380-some ppm versus the typical 3-6 ppm n our water column.

But, considering we have to push to obtain a 30ppm level with 100% CO2 tanks... not real sure how you'd manage much of an increase with regular air... fill the tank with diffusors, lol!

[eleontie]

I think we were a little on parallel tracks. I thought you were referring to having air bubbled into the tank while also injecting CO2 at the same time ( in this case I think the CO2 will escape into the fine bubbles , as it is hard to image air so finely misted into the water column that it will completely dissolve).
Of course if you just want better diffusion from air, smaller bubbles will help. My mistake.

Eugen

[ingg]

Nope, we are on parallel paths, just took me a few more steps to get ot the futility of trying to use air - knew there was a reason we buy CO2 tanks, hehehe...

I was thinking 3% CO2 in air, not .03% (that's 300 ppm, right? Too tired to write it out, been some long days!).... heh, makes it tough to actually use it!

[Sonny Disposition]

Hope I can clarify. When I asked my original question, I was just asking about bubling air into a tank, with out the use of pressurized CO2. I've switched several tanks over from htb to corner box filters. Don't know if it's my imagination or not, but there seems to be less algae, and the plants seem to be a little thicker. So I was wondering if air bubbles could marginally increase the amount of CO2 in the water column, just like they marginally increase the oxygen in the water column.

[ingg]

Yeah, we're thinking it through slowly..

I think maybe technically the answer could be yes, but it is so marginal that I'd probably look elsewhere for the reasons honestly.