# [Wet Thumb Forum]-CO2 into the roots?



## oside (Sep 14, 2004)

Would it be OK to run the co2 line under the substrate & have it release into the root system of the plants? Or is the co2 required in the water column in/near the leaves?
Matt B


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## oside (Sep 14, 2004)

Would it be OK to run the co2 line under the substrate & have it release into the root system of the plants? Or is the co2 required in the water column in/near the leaves?
Matt B


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## Rex Grigg (Jan 22, 2004)

CO2 traditionally has been dosed into the water column. As far as I know the roots of the plants are very poor at utilizing CO2.


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## imported_baj (Aug 5, 2004)

How do you plan to introduce the Co2, is there a concern of having the outlet blocked by the gravel and have a messy (DIY) or dangerous (pressurized) situiation? The next question is what is the benefit of introducing the CO2 this complicated way?


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## Robert Hudson (Feb 5, 2004)

I always wanted to try that. Hydroponic systems feed C02 drip into the root system, but it is still in water that passes thru the roots.


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## Roger Miller (Jun 19, 2004)

I don't think that running CO2 gas directly into the substrate is going to do you very much good. It will have no opportunity to mix with the water. It will probably build up in the substrate until it forms bubbles big enough to break out and rise to the surface. The bubbles will stir up the substrate and make a mess.

A reverse-flow undergravel filter with CO2 in the incoming water would work better. A system like that would be particularly useful if you are growing Isoetes ferns.


Roger Miller


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## Rex Grigg (Jan 22, 2004)

Actually Robert I think that most people growing plants with the hydroponic method just inject the CO2 into the air. At least that seems what all the hardware is designed to do. The CO2 testers used by herb growers test in the range of 5000-10,000 ppm and I don't think you can get those levels in a solution.


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## oside (Sep 14, 2004)

Thanks for the replies - I am putting together a "theme" tank (w/fish) & I am trying to hide any/all equipment. I was thinking of placing the substrate over a under gravel filter (just the plastic bottom piece), possibly covering the filter with screen. Then running the co2 line underthe substrate & into the "filter" area with a fine bubble airstone. Since it sounds like this will not be of any benefit,then how about if I made a cave, like an upside down cup, that the bubbles collected into. Does this work? How much surface area is required for approx. a 30 gal tank? Or, is an agitator reqiured to ge the CO2 into the water?
Sorry for the newbie questions, I've always loved plants, just never really had many aquatic plants in aquariums.
Matt B


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## Rex Grigg (Jan 22, 2004)

How about an external CO2 reactor?


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## JamesHoftiezer (Feb 2, 2003)

If you're using a canister filter an external reactor is the best option. 

Even if you don't use a canister you can still get an external pummp and put something together.

Last option is to just make an internal reactor that is very small and hide in the back corner towards the bottom.


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## JERP (Feb 4, 2003)

I'm hardly a plant biologist, but I believe that plants respirate though the leaves for both CO2 and O2. That would make sense since that is where the photosyntesis occurs. Gas exchange occurs at the leaves, nutrient exchange occurs at the roots.


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## SCMurphy (Jan 28, 2004)

Aquatic plants can absorb some CO2 through the roots but the roots are a part of the plant that respires CO2 all the time. There is plenty of CO2 in the substrate with out adding more, even for Isotetes which prefer to uptake CO2 from the substrate. I don't know if Hydroponics uses water to feed CO2 to plants but Hothouses produce CO2 from propane for Gaseous delivery when they suppliment it.


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