When ever I vacuum the gravel in my 75-gallon planted aquarium air bubbles come up with the dirt. They don’t smell at all and there seems to be more of them in the dirtier areas of the substrate. Is this something I should be worried about or are they harmless? Thanks.
Why am I getting air bubbles in my substrate?
- Thread starter Jeremy S
- Start date
Just a few quick questions to help establish an idea of what your situation is.
How much / how often do you feed? What fish are in your tank? and How often do you clean?
How much / how often do you feed? What fish are in your tank? and How often do you clean?
Ok, just checked your tank specs (maybe I should have looked there first? 
) Georgeous tank by the way! I should be asking you for advice.
Your tank cleaning schedule is pretty good. If you keep your tank as trimmed as what I see in the pics, I don't think you have a vegetative rotting problem. Your bio load looks pretty full though so there may be excessive poop. So it leaves one question: how much and how often do you feed?
) Georgeous tank by the way! I should be asking you for advice.Your tank cleaning schedule is pretty good. If you keep your tank as trimmed as what I see in the pics, I don't think you have a vegetative rotting problem. Your bio load looks pretty full though so there may be excessive poop. So it leaves one question: how much and how often do you feed?
Sounds as if some gases might be getting trapped. And this could be due to the waste you have in this tank but after you answers Mataks q's we should be able to help you more. 
Or it may be only denitrification in the substrate - N2 is odorless, as is CO2 (another possibility).
Any undisturbed substrate of sufficient depth and appropriate particle size will have some denitrification, so a lot of planted tanks have such without it being noticed.
But to answer Matak's question, increased organic load - whether from original use of organics in the substrate or build-up of organics over time from feeding, plant debris, etc. - will definitely promote a steeper O2 gradient in the substrate, which in turn boosts the possibility/probability of gas bubbles. CO2 and N2 and harmless. With more severe anaerobic conditions from higher organic loads, real anoxia, you can get iron precipitation, H2S or methane generation. In undisturbed substrates even those are not dangerous (Diana Waldstad style tanks). This is because those gases are normally ozidized by bacteria before the reach the top of the substrate. If you disturb the substrate, and by this release them, they can cause problems. Very high organic substrates can also "leak" small amounts of toxic gases into the water column - this is classic dirty substrate issues with bottom dwellers, especially fish such as dwarf Cichlids and Corys which do some routine substrate low-level disturbance, being affected or killed first, schoolers and such only later.
HTH
But to answer Matak's question, increased organic load - whether from original use of organics in the substrate or build-up of organics over time from feeding, plant debris, etc. - will definitely promote a steeper O2 gradient in the substrate, which in turn boosts the possibility/probability of gas bubbles. CO2 and N2 and harmless. With more severe anaerobic conditions from higher organic loads, real anoxia, you can get iron precipitation, H2S or methane generation. In undisturbed substrates even those are not dangerous (Diana Waldstad style tanks). This is because those gases are normally ozidized by bacteria before the reach the top of the substrate. If you disturb the substrate, and by this release them, they can cause problems. Very high organic substrates can also "leak" small amounts of toxic gases into the water column - this is classic dirty substrate issues with bottom dwellers, especially fish such as dwarf Cichlids and Corys which do some routine substrate low-level disturbance, being affected or killed first, schoolers and such only later.
HTH
I would guess then that a large buildup and/or release of any kind of gas is unlikely in a RFUGF, correct?
That depends on whether or not you always remember to vent the RFUG powerhead(s) after water changes. There just might be folk here who have been known to forget such basics - :shake: - do not ask how I am sure of this. But that gas is air, and not an issue unless it is blocking flow.
But you are correct - RFUG (so long as the prefilters are cleaned with any frequency) seems to me impervious to buildup, organic or otherwise, and the oxygenated water flow will negate any possibility of anaerobic or anoxic areas.
But hey, I'm prejudiced toward RFUG, I've been using it for Cichlids (the whole justification and need for my over-engineered RFUG) and BW puffers (as messy as Oscars, and need the buffering offered by coral/aragonite substrates, esp. with RFUG flow through that substrate). I'm even currently playing with Tom Barr's cast-off use of planted RFUG with pure water column fertilization.
http://www.aaquaria.com/aquasource/rtrrfug.shtml
But you are correct - RFUG (so long as the prefilters are cleaned with any frequency) seems to me impervious to buildup, organic or otherwise, and the oxygenated water flow will negate any possibility of anaerobic or anoxic areas.
But hey, I'm prejudiced toward RFUG, I've been using it for Cichlids (the whole justification and need for my over-engineered RFUG) and BW puffers (as messy as Oscars, and need the buffering offered by coral/aragonite substrates, esp. with RFUG flow through that substrate). I'm even currently playing with Tom Barr's cast-off use of planted RFUG with pure water column fertilization.
http://www.aaquaria.com/aquasource/rtrrfug.shtml
That's great news for me. Would removing the power head from the UGF plate tube achieve 'venting'?
It's good to see that not everybody is on the UFG bashing bandwagon. I do see their point in some issues, but I believe those issues can be satisfactorily dealt with.
BTW Jeremy, my apologies for semi hijacking this thread. I hope it is still of some use to you.
It's good to see that not everybody is on the UFG bashing bandwagon. I do see their point in some issues, but I believe those issues can be satisfactorily dealt with.
BTW Jeremy, my apologies for semi hijacking this thread. I hope it is still of some use to you.
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