# Large mysterious gas bubbles coming out of substrate.



## awohld (Dec 11, 2005)

I'm using several inches of Turface MVP Pro for my substrate. I've had the tank up for 4 or 5 months, had fish for two months, and plants for 2 weeks.

Lately, last week, I've noticed large gas bubbles erupting out of the substrate that are about as big as a 1/2 tsp of air.

Does anyone else have this? Any idea what this gas is?


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## Riba (Feb 9, 2006)

Does it smell like rotten eggs? Then it might be (the undesirable) Hydrogen sulfide gas.


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## yildirim (Nov 25, 2004)

or else it could be the cumulated o2 from the pruned roots of some plants, esp echin' types, just like the pearling from the leafs but this time from the tips of the roots, unless it is not as riba mentioned caused by anaerobic pockets.


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## trenac (Jul 16, 2004)

Malaysian Trumpet snail (Melanoides tuberculata) will help keep the substrate turned over preventing it from becoming anaerobic.


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## Bert H (Mar 2, 2004)

How deep is your substrate? Without mts a deeper gravel is more likely to get some H2S gas forming.


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## trilinearmipmap (Mar 8, 2005)

Or Nitrogen gas, same as nitrogen gas bubble formed in saltwater deep sand bed systems, there is a lot written about this on the saltwater boards.

You could trap a sample of the gas in an inverted glass container, then test it using the match test.


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## snowy (Jun 6, 2006)

awohld, you need to give more information about your setup.

Is there anything mixed with the Turface? Exactly how many inches is "several"?
Are you using CO2 or doing any regular dosing of ferts?
How are the recently added plants doing - are they growing well, or not at all? Are any going brown or floating out of the substrate?

You say the tank has been filled for a few months and fish for several weeks, but plants added only recently. This suggests two possible sources of the gas bubbles.

On one hand it could be that conditions in the substrate have gone bad over time and produced Hydrogen Sulfide. There may not have been enough of it at first to cause any bubbles, but after the fish were added their waste or uneaten food could have become trapped in the gravel and started to decay. To the recently added plants it may have been toxic enough to damage their roots or planted sections, which in turn have started to rot and which could be the cause of the bubbles - if they are Hygrogen sulfide.

Conversely, as yildirim suggested, the recently added plants may be doing so well that they are pearling from the cut stems planted into the gravel. I recently observed this myself with some fresh Wisteria. However this occurred under strong lighting and with the addition of CO2, hence the need to know what other factors are at work in your tank.

From what I gather Turface is a ceramic substance and should be inert, but did you test to see if it had any effect on the water conditions? Even though it stats that it's intended to allow good aeration, it is designed for terrestrial use and may perform very differently when submersed for extended periods.


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## SnakeIce (May 9, 2005)

I put my Soilmaster select charcoal into my tank dry, without washing it, and filled slowly. The first few days I had a number of large bubbles an hour comeing up from where the substrate had held on to it.

If turface is anything like SMS and Schultz profile it is my experience that in the beginning they hold on to large amounts of air. I still get large bubbles come up every now and then and especially when I disturb the substrate.

I set the tank up just over a week ago, and only the top 3/4' to an inch is totally free of bubbles. A plant root pushing down through the grains may be just enough to kick those bubbles left in your substrate out.

I could be wrong but this is a possibility


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