# Add carbonic acid instead of CO2?



## mordalphus (Jun 23, 2010)

Carbonic acid is the CO2 dissolved in water... First off, where would you get your hands on carbonic acid, then how would you be able to dose it into your water?

I think the much more simple method is diffusion of carbon dioxide in water.

After all, it's the CO2 that plants need to grow, maybe they wouldn't do so well on straight carbonic acid.


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## BigBadBurrow (Sep 14, 2010)

I have my sources lol

But in theory, if you could source carbonic acid could you add it and achieve the same thing? I'm not gonna start doing it, I wouldn't know where to start in terms of dosing. But in theory, it would work wouldn't it...?


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## mordalphus (Jun 23, 2010)

That's the thing, I'm not sure if carbonic acid is just a disposable bi-product of carbon dioxide diffusing into water, or if it's the actual fuel for the plants. I wouldn't think it would be, since emersed plants use straight carbon dioxide gas. You'd think that immersed plants would be the same. 

But nature is a crazy beast, and you never know what she's gonna do.


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## jaafaman (Jun 4, 2011)

mordalphus said:


> _That's the thing, I'm not sure if carbonic acid is just a disposable bi-product of carbon dioxide diffusing into water, or if it's the actual fuel for the plants. I wouldn't think it would be, since emersed plants use straight carbon dioxide gas. You'd think that immersed plants would be the same. _
> 
> _But nature is a crazy beast, and you never know what she's gonna do._


What is the target product of biogenic decalcification?

And didn't Takashi Amano start out his CO2 experiments with carbonic acid (club soda)?...


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## DarkCobra (Jun 22, 2004)

Carbonic acid is unstable, and quickly decomposes back to CO2 and H2O; to later recombine. Between the constant creation and decomposition of carbonic acid, very little of the CO2 dissolved in water actually exists as carbonic acid at any moment in time.

So unlike other acids (sulfuric, nitric, etc.), concentrated carbonic acid cannot exist. Even if you could somehow instantaneously summon it into existence, it would decompose so rapidly into CO2 and water that it would turn its container into a bomb!

If I recall correctly, the maximum carbonic acid concentration is a mere three times the amount in a can of soda. There have been some successful experiments supplying carbon to plants by regularly pouring in sparkling water; but the amount and expense required makes this a novelty rather than a useful method.

Sorry. It was a good idea though. 

(EDIT: Just read that you "have your sources". Since carbonic acid at a useful concentration is impossible, you may have seen _carbolic acid_ instead. Don't confuse the two. Carbolic acid is a highly corrosive disinfectant, not a source of carbon.)


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## BigBadBurrow (Sep 14, 2010)

Yeah, I'm not sure either. But chemically speaking if you fully diffuse CO2 in H2O you get H2CO3, and no bi-products, soooo.... what's the difference to just adding straight carbonic acid?

Also, aquatic plants don't strictly speaking absorb gas - aquatic plants don't have stomata because they're submersed in water all the time, so there is no gas to absorb. 

If I had a spare tank and could source some carbonic acid I'd give this a try on some sacrificial plants. But sadly I have neither :- (


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## BigBadBurrow (Sep 14, 2010)

@DarkCobra - ahhhh ok! I wondered why no one had done it because it seems like such an obvious thing to try. Also explains why no where sells carbonic acid lol


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## Optix (May 31, 2011)

aquatic plants do have stomata...ever heard of pearling? and there is plenty of gas in water...how else would fish breathe?


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## GDP (Mar 12, 2011)

jaafaman said:


> What is the target product of biogenic decalcification?
> 
> And didn't Takashi Amano start out his CO2 experiments with carbonic acid (club soda)?...


Yeah he did, lol.


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## BigBadBurrow (Sep 14, 2010)

Optix said:


> aquatic plants do have stomata...ever heard of pearling? and there is plenty of gas in water...how else would fish breathe?


Yup, heard of pearling, but I don't know what kind of cell produces it.

There seems to be some confusion over whether aquatic plants have Stomata. Some places say they do:

http://www.ehow.com/list_6560781_features-aquatic-plants.html

and others say they don't: 

http://www.eoearth.org/article/Aquatic_plants?topic=58075

Who do you believe? God bless the Internet!

I must say I didn't think they would because fully submerged aquatic plants don't come in contact with gas, and instead absorb nutrients through the leaves. But then there's pearling where oxygen is being produced by the plant, so does that mean there is stomata...?

Like I say, I'm a little confused by it at the moment.


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## BigBadBurrow (Sep 14, 2010)

I think the places that say they do have Stomata are referring to aquatic plants that are rooted in water but leaves are above water, such as water lettuce, or reeds. But plants that are fully submerged in water do not have Stomata, and just produces oxygen through pores in the leaf when photosynthesis occurs, not necessarily through Stomata.

This is also backed up by what I've read about lillypads; they have Stomata on the upper-side of the leaf because they're in contact with gas, but no Stomata on the underside of the leaf because they're not in contact with gases, so has no need for them.

Like I say, I could be wrong, but that's the gist of what I've read.


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## Sharkfood (May 2, 2010)

Not every plant is the same of course. Most aquatic plants have stomata. The difference between emersed and immersed plants is that there are no guard cells, so the plant pores cannot close. There's no need to retain water. Some plants with extremely thin leaves may not have stomata because there is no need for them. The *gas* in the water can diffuse directly across the membranes.

Lily pads may not have stomata on the underside of their leaves because there would be absolutely no point to them. The same reason we don't grow feet on our heads.


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## Hoppy (Dec 24, 2005)

BigBadBurrow said:


> Yeah, I'm not sure either. But chemically speaking if you fully diffuse CO2 in H2O you get H2CO3, and no bi-products, soooo.... what's the difference to just adding straight carbonic acid?
> 
> (


Not true. If you saturate water with CO2, you have a mix of dissolved CO2 in water with a little carbonic acid and some carbonates, depending on the KH of the water and the temperature. Dissolved gasses are not molecularly combined with H2O, just dissolved. Similarly, if you saturate water with oxygen, you don't get hydrogen peroxide, just water with dissolved oxygen.


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## jreich (Feb 11, 2009)

BigBadBurrow said:


> Yeah, I'm not sure either. But chemically speaking if you fully diffuse CO2 in H2O you get H2CO3, and no bi-products, soooo.... what's the difference to just adding straight carbonic acid?


h2co3 is the biproduct.


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## astrosag (Sep 3, 2010)

Hoppy got it right. Most of the CO2 does not chemically bond with the water molecules...carbonic acid is just a byproduct. Most _dissolves _into the water.

Similarly fish don't somehow split the oxygen from H2O, they breathe the oxygen _dissolved_ in the water.


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