Anaerobic Bacteria in Freshwater Aquariums?

[Toby_H]

In this conversation I would like to exclude products that remove ammonia directly, preventing the development of nitrates… I would like to focus on the use of Anaeobic bacteria used in the denitrification of nitrates into nitrogen gas in freshwater tanks only……

There are some Media Manufacturers that claim their Media supports Anaerobic Bacteria… But I have never once heard of a (healthy) freshwater tank not accumulating nitrates as a result of the nitrification process… Despite the fact many people use (what I consider) excessive amounts of Bio Media…

So if you use a Media that boasts being able to support Anaerobic Bacteria… please share your experience as to whether or not you believe they do… and to what degree the effect is…

 

[12 Volt Man]

any media can support anaerobic bacteria, but you need the proper conditions (very low to zero dissolved oxygen) in order for them to thrive.

in normal tanks, this doesn't exist unless you have undisturbed pockets in your substrate.

is this what you are getting at?

 

[Toby_H]

is this what you are getting at?

Sort of...

Some Media Manufacturers (Seachem's Matrix for example) claims it offers an environemnt which allows Anaerobic Bacteria to thrive in typical conditions... without using a special DeNitrator as a seperate filter...

Personally I don't believe it for one minute... but since I rarely use Bio Media at all, I wanted to give others with more expeirence with this kind of product a chance to share their experience to possibly change my mind... or to prove my point...

And in case your wondering... I have nothing up my sleeve on this one

 

[swede]

please correct me if i am wrong, but isn't having the necessary pockets to develop anaerobic bacteria detrimental to your tank and can lead to pockets of hydrogen sulfide?

 

[Noto]

So it is said...personally I don't believe in the sulfide menace. My biggest tank has 10" of substrate, never stirred- you better believe there's some anaerobic pockets in there!

 

[Toby_H]

So it is said...personally I don't believe in the sulfide menace. My biggest tank has 10" of substrate, never stirred- you better believe there's some anaerobic pockets in there!

Fresh or saltwater?

 

[Toby_H]

please correct me if i am wrong, but isn't having the necessary pockets to develop anaerobic bacteria detrimental to your tank and can lead to pockets of hydrogen sulfide?

According to Wikipedia - http://en.wikipedia.org/wiki/Denitrifying_bacteria

Unlike its antithesis, denitrification tends to produce large amounts of by-products.

Although it does not mention what any of these by-products are....

 

[cchhcc]

I too think the sulfide issue is an exaggeration.

NC, I've actually experiemented a bit with Matrix and the like..... No success! Funny, the last time I used Matrix was in a canister for the purpose of colonizing AEROBIC bacteria! Hahaha! At the end of the day, Matrix is just another sintered glass type media. With the right setup (exceptionally slow flow, very long contact time, etc.) almost any media could be made to work in a denitrator..... but I've always had limited success even then.

 

[Noto]

Fresh or saltwater?

Fresh. It's definitely producing gas- I can see little bubbles trapped against the glass, and occasionally see some rising to the surface.

 

[12 Volt Man]

from what I understand, denitrification produces a few different gasses depending on the specific anaerobic bacteria involved.

not all anaerobic bacteria will produce hydrogen sulphide, only those that reduce (feed) on sulphur compounds can.

some of the gases that can be liberated during denitrification are:

Nitrogen gas
Nitrous oxide
Hydrogen Sulphide


most of the time, the bubbles that you see are not hydrogen sulphide, but nitrogen gas.

I work in wastewater treatment, and in the settling tanks, when the sludge blanket at the bottom gets too thick, we get bubbles of nitrogen gas coming up via the denitrification taking place at the bottom of the tank, since the blanket has little to no D.O in it.