# air that comes up from the substrate



## pyrrolin (Jan 11, 2012)

I have sand or gravel over potting soil in my main tanks. I Just did a bit of plant moving in both and I did see air bubbles come up from the substrate on both tanks.

I did a test for ammonia and nitrites on the first one not long after finishing in the tank and nothing showed up.

Did the same for the other tank and also nothing showed up.

In the past when I have done major plant changes I have had ammonia spikes and lost a few fish.

My question is, would any effects from the air coming up from the substrate be immediate or does it take hours for any effect?


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## coldmantis (Apr 5, 2010)

Kill all my fish and shrimp within 30minutes to an hour when I did a major pull of amazon swords on a dirted tank. You can tell the water is poison if you smell sewer.

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## pyrrolin (Jan 11, 2012)

my sense of smell sucks so that wouldn't help


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## coldmantis (Apr 5, 2010)

pyrrolin said:


> my sense of smell sucks so that wouldn't help


No you would smell this one, it stinks up the whole room

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## pyrrolin (Jan 11, 2012)

I have had problems before with fish dieing and didn't smell it.

Doing a 50 percent water change just to be safe.


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## bob123 (Dec 31, 2009)

It is not air bubbles that you see, it is gas bubbles from the decomposition of waste which could be deadly if the amount is high enough, some fish can take more than others. I would do a 50-75% water change each day for two days just to be safe. When you vacuum your gravel during water changes this will help eliminate or at least reduce the gases. Good luck.


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## solarz (Aug 31, 2010)

I've had bubbles from substrate, but have never experienced any ill effects. I credit this to the fact that I have an army of MTS burrowing through the substrate.


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## BillD (Jun 5, 2006)

this is a good reason not to use a high organic soil mix.


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## solarz (Aug 31, 2010)

BillD said:


> this is a good reason not to use a high organic soil mix.


That's a good point, I've only used mineralized top soil.


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## Kimchi24 (Mar 22, 2013)

I've lost a hell if a lot of shrimp this way. I was told to poke the substrate to release the gas at smaller quantities. Even the small amount I was poking off became too much for my shrimp. Needless to say, I never dirt my tanks now. I use flour ire instead haha


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## solarz (Aug 31, 2010)

Kimchi24 said:


> I've lost a hell if a lot of shrimp this way. I was told to poke the substrate to release the gas at smaller quantities. Even the small amount I was poking off became too much for my shrimp. Needless to say, I never dirt my tanks now. I use flour ire instead haha


What soil did you use?


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## Lee_D (Jun 11, 2010)

It's likely CO2 / Methane from the break down of organic compounds. If the fish die because of it, it likely has more to do with the CO2 replacing the Oxygen in the tank. The other possibility is that other, more toxic break down products are released when you disturb the soil.

Lee


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## pyrrolin (Jan 11, 2012)

One tank that I haven't had problems with but its a relatively new setup is miracle gro organic choice potting soil, the older setup that has had problems after massive plant movement is some other brand of organic potting soil which I don't remember the name of.

Twice in the past after moving many plants I have had a couple deaths.

I did 50 percent wc a couple hours after moving plants last night and all is good now.

I can't remember for sure if I had tested the water after the deaths and saw spikes. I did test last night after moving plants and no spikes.


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## Fishfur (Mar 4, 2012)

The unfortunate thing is that you can have anaerobic decomp' going on beneath the substrate, and it can produce a lot of toxins our test kits can't test for. Not nitrates or nitrites or even ammonia, but things like methane, and Sulfides which are responsible for that rotten egg smell, though maybe you can't smell it. To me it smells like stagnant swamp water or sewer gas. Hydrogen sulfide is pretty toxic stuff.

If there is enough organic matter for them to eat and enough anaerobic bacteria in an oxygen free area, which can be anywhere under substrate that is excluding oxygen, they can produce a lot of toxins. Shrimp can be seriously affected if hit with just one bubble of the 'swamp gas'.. fish can take varying levels of it, but if it also has a lot of CO2, it might just suffocate some fish before it gasses out of the water.

If you are seeing gas bubbles come up when you pull plants, I'd do major water changes asap. I'd try to keep the fish contained away from where any gas is coming up and poke the substrate all over to find any other pockets of gas and release them, then do another water change.

Awhile back I drained the content of a potful of lotus to get some critters I could see swimming in it. Got a lot of mucky silt and sand with them. All went into a 2.5 G tank, and the silt settled quickly enough, leaving the water clear. All seemed well but I soon noticed gas bubbles rising from the silt. It wasn't more than a half inch deep in one corner, less than a quarter inch thick elsewhere. Smelled like swamp gas.. and I had to siphon it all out, then separate out the critters, which were ostracods for the most part.

The lotus pot may have been stagnant at the time I drained it, though I noticed no odour. But there was most surely anaerobic decomp going on in the silt, which was so fine I can only assume it was choking out the oxygen from the water. The amount of gas produced surprised me, from such a small amount of silt. Plenty of bits of dead leaf matter in it, so no doubt other organics as well.


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## pyrrolin (Jan 11, 2012)

ok, thanks, so I can't test it then. So I will always do a large water change after a large plant moving just to be safe. That was what I needed to know, thanks Fishfur


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## Fishfur (Mar 4, 2012)

NP, pyrrolin. I had a nasty case of swamp gas early on when I got my first tank going again, thanks to my being way too generous with the feeding. No soil, just Eco complete. I had no clue what it was at first, but it sure smelled bad. The gas was really foul, even my tank water reeked like a stagnant swamp, especially after I'd stirred it all up to release it all. 

Essentially did a total water change in 3 steps to get the stink out after that. 

I did the water changes the same day I discovered I had gas bubbles coming up, once I learned what they were. The smell is certainly a clue that it's not something you'd want around for long. I count myself very lucky I didn't lose any stock over it, though at the time I didn't have that much in the tank, which was a good thing.

Once the water cleared up and it smelled ok again, I got MTS, to help turn the substrate, cut way back on feeding, and now, periodically, I stir up the substrate to make sure there aren't any pockets the snails have missed, and then do a filter clean the next day, because they'll be clogged with all the crap I stirred up. I realize that's not really an option in a dirted tank of course. 

One of the joys of tending to overstock a bit is you do get more buildup, especially around the base of rocks, plants and the sponge filter. I often find there is some gas under the filter, though it does not smell too bad, I assume because I don't let it go too long without checking. The sponge filter does pull water in and through, so I suppose it makes sense there'd be more organic buildup near and under it than most other places.

But every time I lift a rock or wood piece, there's gunk under there, despite having a strong filter flow and a Koralia nano pump running non stop, and the sponge filter. Yet one more reason I'm looking forward to those aquaponic troughs when I get them, I'm hoping they'll pull more gunk out, and the roots of the plants should use it up.. they'll be essentially giant bio filters once they're established.


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## pyrrolin (Jan 11, 2012)

I have a pair of BN plecos in a tank with playsand and a large number of chunks of Mopani wood. I took out a few plants I didn't need due to excess amount and made room for some plants I removed from another tank. I noticed much of the wood was getting buried in the sand so I picked them out of the sand and got a bunch of bubbles. I quickly did about 60 percent wc to be safe. I have learned my lesson I hope.


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