Strange Substrate Smell

[Gideyon]

Even though my parameters were all good, and nitrates were below 10ppm, I did a 50% water change in hopes of helping my betta out. He's been not eating, and I'm curious about his swim bladder due to visual and swimming peculiarities.

I typically don't do this, but I removed all the decorations before the gravel vac.   That obviously stirred up the substrate and all the debris.  And there came this very strong smell.  

I've heard this type of smell describing a tank with high ammonia. But I was measuring 0ppm.   Was this just the smell of shaken up waste?   Did I give my tank an ammonia spike by doing that?  

Was this the smell of mulm from my possibly decaying IAL? 

Anything I should do or look out for?

 

[Cory]

Most likely hydrogen sulfide gas if it had a rotten egg type smell.

[Gideyon]

That may describe it.  Nothing to worry about?   I'll have to read up on it

[Gideyon]

6 hours ago, Cory said:

Most likely hydrogen sulfide gas if it had a rotten egg type smell.

After reading on this, that sounds bad.  Granted it's just one source, but it said in order to avoid a lethal build-up, only have 1" gravel.  But I put 2-3" because I also read that is best for beneficial bacteria.

This anaerobic gas, while I've never heard it actually named hydrogen sulfide, I've always thought to be a problem with sand substrates. I guess gravel is no exception. 

I guess my desire for a low maintenance tank won't be as low as I thought. More vacuuming.....

Unless I go with plants, they say.... 

 

Edited April 20, 2021 by Gideyon

[Fish Folk]

6 minutes ago, Gideyon said:

After reading on this, that sounds bad.  Granted it's just one source, but it said in order to avoid a lethal build-up, only have 1" gravel.  But I put 2-3" because I also read that is best for beneficial bacteria.

This anaerobic gas, while I've never heard it actually named hydrogen sulfide, I've always thought to be a problem with sand substrates. I guess gravel is no exception. 

I guess my desire for a low maintenance tank won't be as low as I thought. More vacuuming.....

Unless I go with plants, they say.... 

 

I'm going to shoot from the hip here . . . there's (at least) two major categories of bacteria in an aquarium context: aerobic bacteria (what thrives in your sponger filters, oxygenated media, etc) and anaerobic bacteria (which thrives deep inside substrate, producing the aforementioned smelly gasses (hydrogen sulfide). When we stir up our old aquarium substrate, it often releases those gasses. If you've ever stepped into the edge of a swamp, you might experience a similar stench.

I don't think that you really want to get rid of your anaerobic bacteria. They perform an important function in your eco system  just like anything else. I'd let it be, and allow it all to settle. 

[Gideyon]

I'll have to read up on it from more sources. What I was reading it made it seem lethal and you must take steps to avoid it. 

[darkG]

There seem to be different ideas about the realness of the problem. While hydrogen sulfide is rather unhealthy, indeed many people use thick substrates of every kind with no ill effects ever. If it is a real problem, the related anaerobic bacteria are not worth it. I agree the conventional wisdom is that fine grained sand is the problem. I think maybe the worry is that a big bubble is released all at once, trapped under compact substrate, while an orderly slight outgassing is ok? I guess a not totally clogged substrate won't amass dangerous levels, that's me guessing.

(Additionally, maybe a tight lid can be a problem, the gas is a bit heavier than air and maybe can linger as a cap, leading to problems?)

Finally, we detect it at very low levels, so we possibly overestimate the levels.

[Celly Rasbora]

I was taught to use a lot of gravel for under gravel filter systems and sparse gravel with other methods of filtration. I have barely an inch of gravel in my tank, which makes planting a bit of a challenge. I like that I have more room for the fish, though. 

[Gideyon]

12 hours ago, darkG said:

Finally, we detect it at very low levels, so we possibly overestimate the levels.

This is what I'm understanding now.  What we smell is non lethal amount.

Also, H2S turns into S4 (I think?) when mixed with oxygen, and is not harmful for fish. So if your water is oxygenated (if it wasn't, fish are dead anyway) as soon as the gas hits the water above gravel, it'll become inert. 

This bit of info has me contemplating using an air stone for added measure.  Maybe even putting it within the gravel. I've been wanting to avoid using an air pump for anything because of the noise. But we'll see... 

Edited April 20, 2021 by Gideyon

[Gideyon]

10 minutes ago, Celly Rasbora said:

I have barely an inch of gravel in my tank

I had it this way in the same tank when I had a goldfish.   I knew nothing about fish care at the time. Long story short, it ended badly.  Hindsight, after learning more and more before getting a betta, I realized I didn't give a chance for much beneficial bacteria to grow. In addition to washing filters and replacing media, I had very little gravel.  

Of course the size of the tank was terrible for a goldfish, and not enough bacteria could form to handle that kind of ammonia anyway.

Anyway... One lesson learned was more gravel.  At least for me.   I was going for least maintenance 

[Ryan F]

Coarse gravel should not be able to support large amounts of H2S. It's not able to "cap" the gas. I use a turkey baster (great tool to have for tanking in general) to blow around my gravel a bit. Break up anything that might be sitting around...unlikely as that may be.

[Dwayne Brown]

I have around 2 inches of course sand in my tank and bubbles get released a lot from the substrate. I cut down on this is by using a gravel vacuum when doing water changes. If you stick the gravel cleaner all the way to the very bottom of ypur substrate, and do this all over the bottom of your tank. It should suck up all of the bubbles with other gunk.

[SkarahW]

On 4/19/2021 at 7:59 PM, Gideyon said:

I guess my desire for a low maintenance tank won't be as low as I thought. More vacuuming.....

Unless I go with plants, they say.... 

 

Real Plants are the best! Even just one solid, betta safe plant in your 5 gal. Once I had a planted tank, I never go back to plastic plants. They not only look pretty, but they are so benficial. What's your filtration situation in that tank? 

[Gideyon]

4 hours ago, SkarahW said:

What's your filtration situation in that tank? 

It's a 10g with an Aqueon HOB, replaced the cartridge with a coarse sponge and some ceramics, and a coarse intake sponge.  

I really like my silk plants.   And so does my betta.  I rearrange them every month as well.  The latter is hard to do with live plants.

But I have been tempted to experiment with one vallisneria and see how it does without any additional fertilizer. I just dont like the threat of snails, and the work to make sure it has no snails, just to try it out. Yes... I'm selectively lazy.