Contention of anaerobic conditions

[Soilwork]

I found this article

14.2.4. Anaerobic Myth in the Aquarium

Anaerobic or anoxic conditions simply do not occur in the aquarium.

aquariumscience.org

there are very strong claims based on ‘scientific experiments’ that it isn’t possible to have denitrification occur in an aquarium or if there is, some criteria first need to be met in order for it to occur that is very unlikely.

When I tore my soil substrate tank down years ago. I had to leave the room because of the rotten egg smell that was released. I assumed this to be hydrogen sulphide on the substrate. I remembered from Diana Walstads ‘Ecology of the Planted Aquarium’ that hydrogen sulphide production occurred at a lower redox potential than denitrification, so if I had hydrogen sulphide production it would stand to reason I also had areas where denitrification was possible and was likely occurring.

any thoughts?
Regards
CJ

 

[dwarf cichlid]

Hi Soilwork, I've researched both Dave at "Aquarium Science" views and Diana Walstad book for issues on anaerobic conditions. I've installed a sphagnum peat moss substrate and capped with a fine gravel - but in parts the peat moss is more than an inch deep and partly covered directly with slate rocks (I run out of gravel hehe). If the anaerobic myth is not a myth after all, I have created the perfect environment for anaerobic reactions. So I'm trusting in Dave to be right - after maturing the tank for six weeks I lifted the slate covering the peat - no ugly smelly bubbles emerged maybe too soon? I then recapped the slate on top of the peat moss.

To be prepared I've heavily planted with Amazon Sword and other rooted plants and hope that their roots will invade the moss under the slate cap and provide aeration. I also read that borrowing snails may help to aerate the peat moss - but based on my gardening experience with snails I would not trust the fellas to leave my plant roots alone.

As you did get ugly smells did you notice any problems before the strip down?

Cheers Pete.

 

[Hufsa]

How do I put this..
The author of the articles on that site has a lot of strong opinions and seems to think he has the answer to everything.
Im naturally sceptical of people who have the answer to everything in a world with a lot of shades of grey.
Some of his articles make decent sense while some of them I disagree with strongly, like his hot take that plants are dangerous for fish (paraphrasing).
Claiming everyone else is also an unreliable source doesnt automatically make you a reliable source yourself.
Whole site gets a "eh" from me.

 

[Soilwork]

Hi Soilwork, I've researched both Dave at "Aquarium Science" views and Diana Walstad book for issues on anaerobic conditions. I've installed a sphagnum peat moss substrate and capped with a fine gravel - but in parts the peat moss is more than an inch deep and partly covered directly with slate rocks (I run out of gravel hehe). If the anaerobic myth is not a myth after all, I have created the perfect environment for anaerobic reactions. So I'm trusting in Dave to be right - after maturing the tank for six weeks I lifted the slate covering the peat - no ugly smelly bubbles emerged maybe too soon? I then recapped the slate on top of the peat moss.

To be prepared I've heavily planted with Amazon Sword and other rooted plants and hope that their roots will invade the moss under the slate cap and provide aeration. I also read that borrowing snails may help to aerate the peat moss - but based on my gardening experience with snails I would not trust the fellas to leave my plant roots alone.

As you did get ugly smells did you notice any problems before the strip down?

Cheers Pete.

Hi Pete,

Thanks for the response.

In answer to your question No, I didn’t have any smells prior to tearing the tank down.

The tank was in a great state of health in actual fact but tearing it down was the least fun I’ve ever had.

 

[dwarf cichlid]

Hufsa, I partly agree Dave of "Aquarium Science" is probably the Ken Rockwell of photography fame, and Aquarium Science does provide backup evidence for the advice provided - just as Ken Rockwell provides evidence but I'm gonna stay with those guys until proven wrong - so far it's not happened.

Cheers Pete.

 

[dwarf cichlid]

Hi Pete,

Thanks for the response.

In answer to your question No, I didn’t have any smells prior to tearing the tank down.

The tank was in a great state of health in actual fact but tearing it down was the least fun I’ve ever had.

Hi Soilwork, if I'm able to draw some conclusions it's possible that anaerobic conditions could occur but just use a good gas mask when tearing down an old tank - or drag your kids away from video games and get them to work.

Cheers Pete.

 

[Tim Harrison]

Aquatic sediments are anaerobic by nature and macrophytes have evolved to grow in them but if the sediment is too devoid of oxygen plants have to work harder to uptake nutrients from them. Further, hydrogen sulphide may build up to levels that inhibit root development and therefore plant growth. However, hydrogen sulphide is unlikely to harm aquarium critters since it is quickly oxidised to harmless sulphates in the presence of oxygen.

However, plant roots will oxygenate the rhizosphere through radial oxygen loss, ROL. The key with deep sediment is to plant densely from the outset and to have a well oxygenated water column. Deep sediment might also allow for a more diverse and abundant microbial community in the rhizosphere which would in turn further benefit the health of macrophytes. And therefore, in turn water quality as plants sequester more organic N for growth.

 

[alto]

Aquarium Science does provide backup evidence for the advice provided -

How many of the links to scientific articles did you follow up on ...
I started reading his Fish TB (Myth) - and the first journal article I checked, the authors had a rather different viewpoint (clearly presented in the Abstract) than the opinion stated by Aquarium Science’s Mystery “degreed chemist” Author (for which he used said article as (presumably) supporting evidence)


Funny how those folks writing/publishing in peer reviewed journals don’t share AS’s views

The author will not provide personal details (a “C.V.”). The author has learned the hard way about identity theft.

 

[Andy Pierce]

Why would you want to remove nitrate? I deliberately add 15 ppm on a weekly basis. As to nitrogen gas production, WHERE ARE THE BUBBLES?!?

 

[sparkyweasel]

Aquariumscience says; "Another myth is that there are anaerobic substrates which produce poisonous hydrogen sulfide gas bubbles. This is also patently false."
A statement which would be very difficult to prove to be true. But it is easily proved to be false, for instance by @Soilwork smelling the H2S as described above and every other aquarist who has had a similar experience.

 

[Simon Cole]

It would be easy to collect this gas and have it analysed @sparkyweasel. You can get vacuum test tubes to collect the gas from above the surface and then send the same to a laboratory. I did this for my first degree on composting windrows and it cost relatively little (tend of pounds). i think the statement refers more to whether this is poisonous.

 

[sparkyweasel]

I think I'll save my tens of pounds and trust my cheap nose. If it smells like rotten eggs, it's unlikely to be anything other than H2S.

 

[erwin123]

My 10 year old tank substrate is up to 6inches deep comprising Gex aquasoil and lava rocks/chips. (it was long ago, I was a total beginner and involved trying to create a steep aquasoil slope which sort of levelled off after many years).

As part of my 'renovation' to the tank (which I had basically neglected for several years), I have been going section by section and simply scooping up the two inches or so of the soil and then replacing it with fresh aquasoil. I tried to google 'replace aquasoil' but didn't get much info.

So I wondering whether its ok to continue moving onto a new section and to replace my 10 year old aquasoil like this? I've done about half the tank but so far no fish/shrimp have died and I don't think i saw bubbles coming out when i scooped up the old aquasoil....