Carbon Dosing During Cycling?

I was just reading this article:
Nitrifying Bacteria Facts
and thought of a question that I wasn't able to find searching around on the forums. Would it be beneficial to dose carbon while cycling a tank? The article says that the nitrifying bacteria fix CO2 as their carbon source; if they had a more volatile and available source wouldn't it help them to reproduce and get a better biological filter going?

It is still going to be about 4-5 weeks before I can set up my tank so I was just researching cycling and getting some ideas. I'm going to start with dry rock/dry sand and buy some live rock rubble to seed my tank. And going to use ammonia to get things going, I really don't like the idea of suing a fish

Just an idea from the new guy, but I would love some thoughts on it!

 

I would not run carbon while cycling. I think it might prolong it. Glad to see you are not going to be using fish to start your cycle. Another option is to use a couple deli shrimp. Good luck with your tank.

 

Thanks for the quick reply!

I'm not super concerned about prolonging it, I am really patient, my main idea was to get a larger, healthier, more stable bacteria load.

 

I think he is talking about carbon dosing, not about running Granular Activated Carbon (GAC). A reason a cycle takes a while is not just that the bacteria takes a long time to multiply, but that the bacteria is dependent on levels of organics, which take time to accumulate and for levels to stabilize. So, in theory carbon dosing could speed up a cycle (GAC may do the opposite, as it is very effective at removing organics). However, in practice, I couldn't say what woe actually happen...

 

I doubt you would start off carbon limited. So adding more organic carbon won't help. I would imagine you would have other factors that limit bacteria production. I would message Dr. Tim on here. No one knows bacteria better.

 

Nitrifiers are called autotrophic bacteria - meaning they get their carbon from inorganic carbon sources like carbon dioxide. Adding organic carbon like vodka or the various mixtures available will not help and may hinder the cycling for two reasons: one, it's the wrong form of carbon and, two, the organic carbon will promote the growth of heterotrophic bacteria which will compete with the nitrifiers for micro-nutrients,space and oxygen.

Even if you added carbon dioxide to the water there is no promise of cycling faster because this assumes carbon dioxide is the limiting factor to their growth during the cycling period and I don't think that is true. Plus adding CO2 may cause a pH to drop which the bacteria definitely do not like.

 

Thanks for the reply, Dr. Tim. I think I follow... Sort of; its been a long time since microbiology. So lets see if I get this right. The nitrifying bacteria that is oxidizing the ammonia can only use inorganic sources of carbon (CO2) and the bacteria that carbon dosing promotes (the ones intended to take care of extra nutrients in the water) would start competing during the cycling and would slow it? If I'm thinking about it right, I guess that makes sense.