Air Pump to replace CO2 for optimal plant growth?

[XnSdVd]

Hey guys, been doing a little thinking, if one is merely trying to achieve moderate plant growth and induce fish breeding would it be possible to replace pressurized CO2 with an air pump or just aerate the water using the Bioball+Sump waterfall we see in many marine tanks?

Lets consider for a moment that plants in rivers and streams grow much faster than those in low tech tanks where ferts are dosed monthly. Not as fast as high tech tanks where the plants pearl like oysters on cocaine but like i said, "Moderate" plant growth.

There are 3 reasons i can think of that cause this:

Strong water flow - That's obvious isn't it? More water flow means better circulation of nutrientsright? Not really. Who doses ferts in the wild? Sure you've got the occasional duck dropping some "root monsters" but that's hardly noticable.

More Nutrients - Does a river have a glass sheet at the bottom? Of course not. But it appears that only the top 5 - 15cm of soil in a tropical rainforest(That's us) is fertile! The rest, according to my old geography textbook, is too poor to support plant life. So that puts the average river on the same level as our tanks (my substrate is usually 5 - 15cm deep)

Increased Aeration - HERE'S the big difference! We all know that water "in the wild" for lack of a better term, is acidic because of the tanic and humic acid released by rotting leaves but ALSO because of the increased gaseous exchange which means CO2 from the air mixes with the water. This would happen in our tanks except the amount of water exposed is very little compared to a 2 meter wide forest stream where the water is only ankle deep. All that extra CO2 and O2 seems to do wonders for the plants.

So, is it possible to increase plant growth and lower pH with an air pump? I'll give it a try the next time my canister goes empty.

[ranmasatome]

You are trying to compare our tanks with an entire river ecosystem???????????? that in your reasoning is already well... kinda warped.

[|squee|]

Imho why do plants in rivers grow better than in our non-CO2 tanks is because of sunlight.

It's an interesting thought, but isn't the ppm of CO2 in non-CO2 tanks similar to ambient levels of CO2? Is increasing CO2 concentration by agitating the water possible? Because not only CO2 is being dissolved, other gases too.

It's the sunlight I tell you!

[XnSdVd]

You are trying to compare our tanks with an entire river ecosystem???????????? that in your reasoning is already well... kinda warped.

Lol, it's been a very strange week. But yes, isn't that the definition of a biotope? A simulation of an ecosystem? Also, i believe Valice and Thio switch on air pumps at night and they say their plants are growing rather large. To quote Valice "Aye.. the leaf ah..*shows size with hands* Pwah!"

[medicineman]

It is not easy to dissolve air into the water as in pure (99.xx% actually) CO2.
Air consist of merely 0.04% CO2, compared to 99.xx% from pressurized tank.

The closest where I have seen people keep plant mimicking nature is when they use constant flow of new water from a good water source (clean spring water or clean well) into their tank/pond. No CO2 injection, no artificial light (most of the times shading net is necessary), no water collumn fert. Macros come from rich substrate (often soil mix) and supplemental root tablets (often self made from manure and such), while micros come from that constant flow of new water. More of copying how a natural pond work with water supply from a stream. Water from certain spring and generally water from ground water table contain quite large amount of dissolved CO2 so far as I know.

[Jungle-mania]

I think it is a worthy experiment for XnsDvD to try out and I also have to concur with squee that sunlight plays a major part. But IMHO, I think that having a large water volume also has a big part to play, to mimick such chemical equilibirium at too micro a level would require great amount of dedication.

[PeterGwee]

Imho why do plants in rivers grow better than in our non-CO2 tanks is because of sunlight.

It's an interesting thought, but isn't the ppm of CO2 in non-CO2 tanks similar to ambient levels of CO2? Is increasing CO2 concentration by agitating the water possible? Because not only CO2 is being dissolved, other gases too.

It's the sunlight I tell you!

DOC dude....loads of decomposition happening in the soil/river bed system. It still goes back to the same thing to what a plant really wants.

Regards,
Peter Gwee

[Weirong]

The only experiment I have been trying the past week is testing some floaters in a 3ft tank of aged water (with a base of mulm) next to a sunlight-lit window. No filtration or CO2.
I also hid some Echinodorus species underneath the floaters to see how they respond.

I feel that it's got a lot to do with the sunlight as well so I'm testing just that.