# Solutions for harmful gas buildup in substrate?



## lmhollist (Aug 7, 2009)

Hello all!

I guess I kind of have a weird question on reducing the build up of gases in undisturbed substrate, especially sand. Are there any invertebrates that anyone knows of or uses for that purpose? My boss has kept marine aquariums in the past and is in the process of setting up a new and he says he is able to avoid that problem because of the worms, copepods and other invertebrates that live within his substrate and breed in his sump. In fact, these invetebrates will serve as a major source of food for most of his fish.

Is this possible in a freshwater aquarium? I know that in the wild there must be organisms that live within the substrate, but I never hear of people utilizing this for their freshwater aquariums. Maybe it's the fear of allowing in dangerous worms or just that we don't like creepy tiny bug-like creatures all over the place? But anyway, it seemed to me to be an excellent way of reducing dead spots in your substrate and also providing a natural food source for your cichlids. Is anyone familiar with this at all? Or familiar with any organisms that would provide that kind of service?

Thanks in advance!


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## Toby_H (Apr 15, 2005)

Malasian Trumpet Snails (MTS) are very common. Most of us who have bought a plant from a LFS or chain store have gotten them in our tanks, and once you get them they are nearly impossible to get rid of.

They do burrow in the sand...

Most Cichlids also dig in the sand...

Most of us do not keep deep enough sand beds to really worry about gas build ups...

I've used sand in tanks for between 5~7 years and have kept at least a few hundred gallons of tanks that whole time. I've never once had any issues from such gases building up in my sand........


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## brycerb (Dec 23, 2007)

"The dreaded gas build up question" has been raised many times and has always been answered by: "my freinds, freinds, aunt had that problem." Never any direct experiance.


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## lmhollist (Aug 7, 2009)

I've seen the build-up of small gas bubbles in a little 10 gallon we had going for a fish. They'd start showing up in spite of water changes/shifting the sand around once a week...but anyway.

Basically, I get to be the "friends, friends aunt who had the problem once upon a time". I'm concerned about dead spots in my aquarium... my corys only stir up the very topmost layer of sand on a regular basis, the cichlids like to dig around the rocks (and with the exception of our auratus) don't dig deeply on a regular basis anywhere else. And somehow in spite of all the aquatic plants the roomie and I have purchased, we still don't have any malaysian trumpet snails, just the regular mystery ones that breed like crazy in our livebearers tanks (although our EBJD takes real special pleasure in eating any snails I happen to drop in the tank in an attempt to find something that will do a little burrowing).

Malaysian trumpet snails might be something, but with their whole being a tasty, easy to get at snack for my cichlids, I don't know how well that program will take off. I'm looking for something that is more a constantly lives and burrows in the substrate kind of animal.

Seems like it's either that or going in with a massive wooden spoon every other day and stirring up the sand...


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## brycerb (Dec 23, 2007)

keep us posted.


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## BRANT13 (Feb 18, 2009)

if ure relly worried just stir it up everyother water change. *Toby_H* gave u some good advice....just be sure to not have ure substrate so deep.


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## Toby_H (Apr 15, 2005)

In Latin... Geo means Earth... Phagus means to eat...

So GeoPhagus literally means "Earth Eater"... although "sand sifter' is a more accurate description of wha tthey do... I keep them with my Blue Dempsey and they get along fine...

Khuli Loaches burrow a lot too, although most Cichlids see them as a challenging snack...

So in that tank that get's bubbles... do they make anything bad happen?

I've read a fair biit about the risk and from what I understnad... when they are trapped and building up... they are trapped and do not harm anything...

When they are released they are in direct contact with the water and for that split second they are risking, they are polluting the water and then bloop... they are gone... putting a minimal impact on the water quality.

From what I gather the situation where they become a threat is when they are released from the sand... and then the airbubble gets caught somewhere else... such as in a rock structure with water flowing past it... as in this situation it will continue to leach into the water...

So I'm not saying they are no risk at all... I am suggesting that the risk of them forming is quite small... and in those rarer situations they do form, the risk of anything bad actually happening is very small...

In the same way I could think... keeping a fishtank can cause humidity... and humidity can cause mold... and mold can cause allergies... so I had better get rid of my fish tank...

There is no false logic in any of that... just like there is no false logic in the concern of gas bubbles... but the risk of either is quite small and for the most part quite avoidable...


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## cichlidfeesh (Apr 6, 2009)

Since you have a young EBJD (I think), I would release any gas build-up just to be safe. Do you have a gravel vac? If you do I would suggest using a large one (with a 1.5'' or larger diameter barrel) and siphoning it at a 45 degree angle from the bottom. All you have to do is stick it in your sand all the way to the bottom, and any sand you disturb should fall rapidly back to the bottom. This way you suck up all bubbles and debris at the same time. *Warning - siphoning perpendicular to the substrate will result in sucking up sand*. This is what I do and it keeps the sand nice and clean. I've never had fish die of poisoning, but I've heard of it (very true statement about the he said she said thing), I would just err on the side of caution, especially with a young EBJD.


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## prov356 (Sep 20, 2006)

These gas bubbles aren't that uncommon, at least for me. I've seen them in certain tanks all the time. Put a flat stone in the tank that allows food, etc to get trapped under it but won't allow any fish to dig under it. Wait a while (few weeks) and then lift it up. Gas bubbles will be released and the sand will be black. Will fish die? None of mine have. In tanks where my fish dig a lot, I rarely see it except in crevices between rocks when I siphon. I see it in my brevis tank next to some rocks where they don't dig. I see bubbles come up from underneath the lava rocks in my sump when I move them to vacuum it out. Mulm collects under there, and some denitrification apparently occurs. This gas, if the end product of denitrifcation, is nitrogen gas (N2). Nitrogen makes up 78% of the air we breath, so not toxic to us. As for fish, I guess if you added enough to supersaturate the water and deplete oxygen, you could have a problem. The real threat from denitrifcation that may be going on is that the nitrate is first converted to nitrite before being converted to a gas.

You can see the full process steps here.

I just stir the sand ocassionally, but also wish there were some sand critters I could employ to break down detritus in the sand. But you'd also have to have something to eat them to control the population. If anyone knows of anything, I'd be interested as well.


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## lmhollist (Aug 7, 2009)

cichlidfeesh said:


> Since you have a young EBJD (I think), I would release any gas build-up just to be safe. Do you have a gravel vac? If you do I would suggest using a large one (with a 1.5'' or larger diameter barrel) and siphoning it at a 45 degree angle from the bottom. All you have to do is stick it in your sand all the way to the bottom, and any sand you disturb should fall rapidly back to the bottom. This way you suck up all bubbles and debris at the same time. *Warning - siphoning perpendicular to the substrate will result in sucking up sand*. This is what I do and it keeps the sand nice and clean. I've never had fish die of poisoning, but I've heard of it (very true statement about the he said she said thing), I would just err on the side of caution, especially with a young EBJD.


Yes he is pretty young, he's maybe two or two and a half inches now. Having an EBJD is what causes most of my concern (and we'd like to breed him in the future too, with the goal of getting as many fry as possible to survive). My roomie and I are in the process of finishing a system where, even though his tank will be linked up with our others, the water will have to go through a normal canister filter to get out the big stuff, a home water purifier (the kind that links up under your sink) and then a Turbotwist UV sterilizer. May be overkill, but it makes me feel better. The only remaining problem is his substrate. He hasn't ever shown any tendencies to dig.

I read different things about this bubbles that form ... I've seen where the gas joins up with oxygen molecules in your tank almost immediately after being released, thus making the gas harmless, but it also seems like I've read about people saying how dangerous the build up of these dead spots can be.



prov356 said:


> I just stir the sand ocassionally, but also wish there were some sand critters I could employ to break down detritus in the sand. But you'd also have to have something to eat them to control the population. If anyone knows of anything, I'd be interested as well.


I think it's probable that the cichlids would eat any organisms that ever poked their ugly little heads above the surface. Makes me jealous of my marine aquarist friend. These worms and copepods and such that he uses to clean up the major detritus in his sand are also a source of food for his fish, shrimp, etc. May have found an article on wikipedia about an invert native to African Rift Lakes that may perform this sort of function but I need to look into it some more.

Obviously animals that eat poo just cause more poo, but the goal here is to reduce dead spots. I vacuum my gravel and sand when I do water changes (actually just got a great battery operated one too), but not having to remove rocks and such would be an excellent bonus. I like the idea of trying to create a more natural-esque system by using organisms that provide clean up services in the wild.


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## prov356 (Sep 20, 2006)

I was just reviewing Diana Walstad's book 'Ecology of the Planted Aquarium' because I remembered that she wrote of the gas bubbles that build in substrates. Seems it can be a lot of different things besides the end product of denitrification, some of them potentially harmful like hydrogen sulfide. But, there are a lot of complex processes going on, and often this hydrogen sulfide is oxydized by bacteria into harmless substances similar to the conversion of ammonia => nitrite => to nitrate that we're all familiar with. Bottom line, the chance of something like that harming your fish probably isn't high, but still a good idea to stir up any dead zones occasionally. If we can find a critter to do it for us, all the better.


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## boredatwork (Sep 14, 2007)

Just vacuum your substrate. In my opinion its something that should be done for a lot of reasons anyway.

When I vacuum my sand I will sometimes get bubbles around the edge of the tank, but only at the edges that are exposed to light. Personally I doubt that the bubbles are a result of decaying waste.

The great thing about vacuuming is that when the bubbles are released they are caught in the siphon and get siphoned out of the water. So if the gas is dangerous it is not being dissolved in the tank water.


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## emptyhead (Apr 16, 2007)

I have fairly deep sand beds in my malawi tanks. Pockets of black stinky sand do happen. I just stir the water up when doing water changes.

For planted tanks - no need to do anything to the substrate. Don't disturb it - just let your plant roots take care of the problem. MTS are good also.

For non-planted tanks - manually disturb your substrate. MTS are good if your fish won't eat them.


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## lloyd (Aug 24, 2005)

it has always been my understanding, that if/when substrate cultures of denitrifying bacterias are disrupted, the area involved would experience an instant decrease in d.o. levels, followed by a probable spike of either ammonia and/or nitrite. a further chain reaction of dramatic events could take place if conditions within the enclosure were 'ripe'. whether any particular aquarium set up tolerates this type of experience, without any discerning health issues for the inhabitants, depends wholly on the biological load, the volume of bacterium disturbed, and the sensitivities of each species involved. all of my tanks (27...  ) have very shallow substrate, and a host of diggers and sifters, to help alleviate this very concern from occurring.


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## prov356 (Sep 20, 2006)

> it has always been my understanding, that if/when substrate cultures of denitrifying bacterias are disrupted, the area involved would experience an instant decrease in d.o. levels, followed by a probable spike of either ammonia and/or nitrite


Denitifying bacteria do their work in areas of low oxygen, so there would be an increase of DO, not a decrease if you stirred the sand where denitrification were taking place. Nitrite is one of the intemediate products in denitrification, so it's possible it could be released, but not ammonia.


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## howmany (Jul 1, 2009)

In the past i have had Dojo Loaches, they dig under the sand, to where you cant ever see them.... and my cichlids never messed with them. they are fun to watch, and have great little personalities.


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## football mom (Feb 19, 2006)

"Malaysian trumpet snails might be something, but with their whole being a tasty, easy to get at snack for my cichlids'

I've never had any cichlids that exterminated the MTS population...


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## jrh (Sep 4, 2007)

I don't know if cichlids snack on MTS or not, but they have much harder shells than normal aquarium pond snails or ramshorns.


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## lmhollist (Aug 7, 2009)

I'm not sure about malaysian trumpets yet... somehow I've been lucky (I think?) to have never picked one up even with all the plants I buy. It's not like my cichlids actually crunch their shells... and I don't know what would happen with a larger snail, I feel nervous about putting one in there. But with smaller mystery snails they'll just pick them up and suck out the little snail body. It's actually kind of entertaining to watch.

Dojo loaches sound interesting. There seem to be a lot of burrowing species of fish, but if they're the kind that will really dig around deeply they may be a huge help in an aquarium with deep substrate (like a few of mine). Also found out about a catfish today that pretty much burrows around constantly underneath the substrate. The name escapes me at the moment but they don't get large at all, like in the 3 to 4 inch range for max. growth.


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## lmhollist (Aug 7, 2009)

Just as an update...

The catfish I mentioned before are Banjo catfish ... anyone ever heard of those or kept them in their tanks at all? Anyway, from what I've been told, they love to burrow around underneath the sand and don't get especially large ... around 6 inches. Anyway, was camping this weekend and stopped by a fish store my roomie and I found online just to see what it was about and lo and behold they had banjo cats so we picked up what they had and took them home.

The drive was pretty long, in total it ended up being about 9 hours between leaving the fish store and getting back to the other side of the state. We had the owner prepare some fresh water to bag the fish in (none from the tanks so that way at least there aren't any toxins to start with), we did a water change a little over half wayish to reoxygenate the water and also to hopefully reduce any ammonia that may have built up. Also transported the fish in individual bags inside a styrofoam cooler to reduce temp. fluctuations and also to keep them in the dark where they hopefully felt a little less stressed out.

Anyway, added them into a tank we had set up and they'll be in quarantine for a couple of weeks. Hopefully all five banjo cats make it and then we'll see how they do once we had them to the cichlid tanks that have sand substrate.


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