Question about carbon source for bacteria in gravel.

Harry Muscle

Junior Poster
Mar 17, 2007
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According to Tom's Non CO2 Method article, using mineralized soil, peat, or leonardite under the gravel provides a source of carbon for the bacteria living in the gravel which in turn allows the bacteria to use up oxygen in the gravel, thus allowing better transfer of nutrients to the roots (hope I understood that right :) ).

The question I have is what happens when the carbon source runs out? Does anything else in the tank eventually start to supply the bacteria with carbon? For example does all the "crap" that accumulates eventually in the gravel take over this role of being a carbon donor?

Thanks,
Harry
 

Tom Barr

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Jan 23, 2005
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wit soil,.there's a great deal of Carbon. Same way for the plant's adding a source of leached Carbon to the system, one reason why bacterial action and numbers are higher around plants/roots, another is addition of O2 to sediments by roots, which means the bacteria are also not limited by O2.

Fish waste also adds organic carbon. Going the other way, too much organic carbon, the bacteria go crazy and use up all the O2, depletion of the O2 leads to fish deaths and higher CO2.
Once they run out of O2, then things crash into a foul smelling mess. The rate of loading of Organic matter is a key factor.

If you have a slow rate of plant growth and few fish, plain inert sand, then it's more possible.


Regards,
Tom Barr
 

jonny_ftm

Guru Class Expert
Mar 5, 2009
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Hi,

I miss something here. How then the organic soil (earthworm castings) could avoid the bacteria go crazy? I'm just concerned since I started my nano that way. For now, every thing looks even impressively great
 

Tom Barr

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Jan 23, 2005
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Any form of reduced carbon can provide for the bacteria oxidation.
WC's, soil, Clays, etc, anything with organic matter(OM).

As time passes, the bacteria oxidize the OM. If no new OM is coming in to the system, or at a very low rate, then there's not much "food" for the bacteria to consume and the demand by bacteria on O2 will also be low.
We can oxidize the soil or in your case, WC's, prior to use in the aquarium.

That is why they boil it for 10 min before using it.
You can do this by bacteria and in a shallow pan for 2-3 weeks also(Biologically instead of physical oxidation)

Regards,
Tom Barr