# Sulphur in soil substrate



## Alex C (19 Jan 2020)

Hello all, 

Came home yesterday to a very eggy smelling house (took me a whole to convince my other half my stomach was fine!) , turns out the soil substrate of my tank is releasing, I guess from the smell, some sort of sulphuric gas.

Since going in the plants aren't so doing well, I originally thought it could be under nutrition but having come across this I pulled one up and the roots are less than healthy so it's pointing towards the soil (currently being cycled, no livestock in it). 

Having done some reading there seems to be various bits of information but a lot of it conflicting. Some say its the end for the tank (certainly looking that way for the plants at the moment!) and others say it's gods gift to you and you should be thankful.

Is anyone able to provide any clarity on this? Going with the assumption it's not healthy, any suggestions for the best remedy? Is it something that can be resolved 'as is' or am I safest to rip all the soil out? 

If it's the latter, I assume I can 'hospitalise' the plants without substrate for a period while I sort it all out without too many ill effects (assuming they're not too damaged already)? 

Any help greatly appreciated! 

Alex


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## Simon Cole (20 Jan 2020)

That sounds awful. Could the soil have been contaminated with chimney linings or soot waste?


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## Alex C (20 Jan 2020)

Not that I'm aware of, although thinking back it did end up sat for an unplanned week in a box (wet), I didn't think it would do any harm at the time but maybe I was wrong!


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## dw1305 (20 Jan 2020)

Hi all,





Alex C said:


> turns out the soil substrate of my tank is releasing, I guess from the smell, some sort of sulphuric gas


It is <"hydrogen sulphide (H2S)">, we can detect it at very low levels, below one or two ppb. 





Alex C said:


> pointing towards the soil.


The issue is low levels of oxygen in the substrate, have a look at <"Winogradsky column"> link, and the <"which filter media..."> thread. 

There are a number of reasons why you might have this, the most likely one is that the organic matter component of the soil is decomposing and its oxygen demand has deoxygenated the soil, this is because the rate of oxygen usage has exceeded the rate of oxygen diffusion. Once the <"soil has mineralised"> (the organic matter has oxidised) the oxygen demand will fall, how long that takes is going to depend on all sorts of factors. 





Alex C said:


> ........currently being cycled, no livestock in it.


If you are adding ammonia to cycle the tank? You can stop. Ammonia will also reduce oxygen levels (nitrification is an oxygen intensive process) and it won't help in making the <"aquarium fish safe">. 

If you have some floating plants? they won't help with the substrate, but they should reduce ammonia levels in the tank and help you get through this stage a bit more quickly. 

cheers Darrel


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## Alex C (20 Jan 2020)

Thanks for the response, very helpful! 

I'm not adding ammonia, only thing I've added is plant fertiliser so far, it seems to cycling well though. 

So it sounds like the core of the problem is lack of oxygen in the soil, having looked at the links I suspect it might be on the thick side too (solid 5cm most of the way round).

While the 'easy' option is to go buy a bag of prepared aquarium soil I'm all for a challenge (it's only a failure if you don't learn something in my book!).

My plan, hopefully logical;
- Get the plants out and into a temporary home for a bit of revival. 
- Skim of the sand for reuse later
- Take out approximately half the eggy soil to put in my bosses office (muhaha!)
- Really mix up the remainder to get some air into it and leave it for a few days (mixing every now and again) 
- Add in some gravel or some lava rock (would one be more preferable? ) to add some 'break-up' material to help water flow through the soil and hopefully more oxygen
- Put everything back on top

Is that reasonable or should I just go to the pub? 

Thanks again in advance, much appreciated!


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## Sergey (22 Jan 2020)

Well if you don't want to tear down the tank, there are some measures you can try: 
- Regularly poke the substrate with smth like a sharp stick, that would help release the gas and allow fresh water in; 
- Get the plants with strong root system (e.g. crypts), once they start to grow their roots help keep soil oxygenated; 
- Get some Malasyan Trumpet Snails, they dig through the soil and keep it oxygenated.


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## Alex C (22 Jan 2020)

I dug it up the other night, no fish in at the moment so I didn't have to worry about anything to much. Glad I did too be fair, a lot of the roots were not in good shape. I think I'll have lost a couple of the plants but the others seem to be recovering OK now they're out of the soil. A lot came out black but are slowly returning to white.

Took the sand capping off yesterday and think I may rethink keeping the soil and go for some prepared stuff in this tank. Its certainly going to take a few mouths to sort it self out I think, from looking at it with fresh eyes after the reading Daryll provided. While I'm not in a hurry myself, the tank is in the living room and I'm not on my own in the house!

I won't chuck this stuff though, I'm going to get a big tub and have a go at mineralising it. Unfortunately I don't have anywhere I can lay it out to dry so I guess the approach will be keep it wetted?


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