Are there drawbacks to over carbon dosing?

[Winwood]

Perhaps this has been covered in past threads but I haven't been able to find much info on the topic. The original formula for carbon dosing was to slowly ramp it up to a point where nitrates went to zero, then cut it to half and go from there. Is there any negative effects experienced from keeping the dosage at full strength and giving oneself a buffer?

 

[reefmutt]

I would also really like to know the answer to this.
I would assume the extra carbon that is not getting absorbed by the bacteria consuming n and p, would become extra organic pollution in the tank, but to what effect??

 

[downbeach]

Too much carbon will cause bacteria blooms, which will cause oxygen depletion.

 

[steenmillinder]

can the bacteria boom if there is not enough available nitrogen?

If the tank i heavyly skimmed will det owygen depletion have time to reach any significant level?

Are there bacterial strains that can fixate nitrogen form the air for example from the air/water surface area in the skimmer?

 

[reefmutt]

I suppose you wouldn't necessarily get the bacterial blooms that cloud the water because as steenmillinder pointed out, without nitrogen that particular bacteria wouldn't bloom.
I think what downbeach is referring to is cyanobacteria.
You'd probably get red slime algae and perhaps other types of algea as well..
Not sure what nitrogen might be floating in the air except maybe ammonia if you are cleaning your windows or something...

 

[swcc]

the main dilemma is N becomes depleted before P when dealing with accelerated N bacterial strains...so you have N become a limiting factor and P will rise or not reduce enough. Also, too much and you get cyano(depending on tank nutrient load) and/or O2 depletion as well...
IMO carbon dosing is best left for a tank that has very low/trace N and P and you want to get to zero... if you have N and P in significant amounts, you have to look at cause and effect vs just carbon dosing to hide poor husbandry/filtration/flow issues.

 

[der_wille_zur_macht]

Not sure what nitrogen might be floating in the air except maybe ammonia if you are cleaning your windows or something...

78% by volume of the air in our atmosphere is nitrogen (gas.) Seawater typically contains about 10 ml/L of dissolved N2 though as far as I know it's not biologically important.

 

[Winwood]

Glad to see people responding to this thread. I had thought it had fallen on deaf ears.
In my particular case I have been slowly ramping up with an increase of about 1 ml. of vodka each week. After a month, I am at 4 ml/day. I have seen the nitrates come down from around 20 to under 5 ppm. I was considering keeping the tank continually steady at 4 ml/day but from what I'm hearing, without a steady N source it may cause an outbreak in, which I'd like to avoid.

 

[steenmillinder]

N2 was what i was thinking about, some plants(peas and beans) utilize nitrogen fixating bacterial colonies in/around their rootsystems to provide nitrogen in a usable form(organic formers use them to refertilize the soil)..

Could there be any biologial way of adding more nitorgen compared to phosphate in the form of what kinds of animals you keep? herbivore/carnivore, vertabrate/invertabrate?
If the phosphates introduced are in are what you feed the tank there might be a difference in plant based food versus meat based, and maybe some of the phosphates are bound in metabolites in poo that can be skimmed out?

Or using a combination of sources of carbon? europeans tend to use a blend of vinegar, sugar and alcohole(maybe some strains use more phosphate to build their bodies, and when they die we skim them out)

 

[steenmillinder]

If overdosing alcohole, and there in not enough available nitrogen for rapid microbial groath, would the alcohole not evaporate relatively fast due to the large surface area in the skimmer and lower boiling point?

 

[reefmutt]

"78% by volume of the air in our atmosphere is nitrogen (gas.) Seawater typically contains about 10 ml/L of dissolved N2 though as far as I know it's not biologically important."

:hmm4: D'oh!.. you know, I'm pretty sure I learned that in high school.... can't really remember, though...

winwood, I would think that finding that balance between the amount of carbon source and having just slightly measurable n is the key..

steenmillinder, I didn't even remember that nitrogen makes up a large part of the atmosphere, I couldn't even begin to know the answer to your question..
But its an interesting question..

 

[jerpa]

If overdosing alcohole, and there in not enough available nitrogen for rapid microbial groath, would the alcohole not evaporate relatively fast due to the large surface area in the skimmer and lower boiling point?

The ethanol in vodka is broken down into acetic acid, this is what feeds the bacteria. This happens before the alcohol can evaporate regardless of nutrient levels.

 

[BfishLpond78]

I apologize if this is out of left field...does the same apply for a solid form of carbon in a reactor?

sent from never never land...

 

[swcc]

Glad to see people responding to this thread. I had thought it had fallen on deaf ears.
In my particular case I have been slowly ramping up with an increase of about 1 ml. of vodka each week. After a month, I am at 4 ml/day. I have seen the nitrates come down from around 20 to under 5 ppm. I was considering keeping the tank continually steady at 4 ml/day but from what I'm hearing, without a steady N source it may cause an outbreak in, which I'd like to avoid.

yeah hold steady or you may even reduce it to say three ml. watch n and p. Should it stop lowering or increase up the dose. If you have a salifert test kit you can measure trace levels to a decimal point. when you get down to one or into a decimal drop it in half and maintain.

 

[downbeach]

This article may help to shed some light:

http://www.advancedaquarist.com/2011/3/aafeature

 

[incognitus]

I saw yesterday what happens after over carbon dosing vinegar in a three years old tank low in nutrients.

All high flow areas were full of white bacteria, so all pumps got clogg. Also my front display was full of bacteria and pods, because recirculation pumps lead much flow against it. There was no oxygen depletion. All happend in three days.

 

[jdegrasse]

Perhaps this has been covered in past threads but I haven't been able to find much info on the topic. The original formula for carbon dosing was to slowly ramp it up to a point where nitrates went to zero, then cut it to half and go from there. Is there any negative effects experienced from keeping the dosage at full strength and giving oneself a buffer?

To directly answer this question -- there are no negative effects. In a low nutrient system, a 50% dose is still in excess.

One needs to ramp up the carbon dose slowly to prevent an explosive growth of bacteria. Once the balance has been struck, you can reduce the amount of dosing. This has the benefit of cutting cost and dosing volumes.

Excess ethanol and acetic acid will likely evaporate. Solid carbon stays locked up in the beads until the bacteria consumes it, so that balances itself.

The source of the carbon does not matter.

 

[jdegrasse]

The ethanol in vodka is broken down into acetic acid, this is what feeds the bacteria. This happens before the alcohol can evaporate regardless of nutrient levels.

That is not correct. The conversion from ethanol to acetic acid is not spontaneous and requires a catalyst or enzyme.

 

[Winwood]

Thanks everyone for both directly and indirectly answering my question. Such informative answers.

So to clarify, acetic acid is the molecule formed from adding a carbon source and then is biologically "consumable" by the carbon limited bacteria?

 

[jdegrasse]

Thanks everyone for both directly and indirectly answering my question. Such informative answers.

So to clarify, acetic acid is the molecule formed from adding a carbon source and then is biologically "consumable" by the carbon limited bacteria?

Close.

If you add acetic acid as the food source, the consumed acetic acid is converted to acetyl-CoA which then enters the TCA energy cycle.

If you add ethanol, the bacteria consumes it and first converts it to acetaldehyde, then to acetic acid which then enters the TCA cycle as acetyl-CoA.

This happens because ethanol and acetic acid are normal byproducts of cell metabolism. We humans produce ethanol in our metabolism, but our liver is obviously able to handle the small amount that is produced.

The cool part about this is that most bacteria can metabolize ethanol and vinegar at dilute concentrations (too high and both become lethal which is why ethanol and vinegar are generally aseptic). So there is no need to "seed" the tank with special bacteria (e.g. nitrobacter)

How much is too much? Well, bacteria can grow in 1.5% ethanol. So if you have a 100 gallon tank, 1.5 gallons can be pure ethanol. :spin2: