deadly bubbles??

[niqolas619]

I was reading about maintaining a sand aquarium and everyone says that you have to run through the sand every once in a while because air bubbles and stuff gets trapped in the sand and this could become poisonous if it just sits there. This got me thinking - are the bubbles that get formed underneath my rocks deadly if they sit there for a while, too? You know, the ones that form cuz of your filters or bubble wands or whatever.

[cocoa_pleco]

if you have regular gravel now, youre okay. what builds up in sand tanks is CO2 pockets, deadly. airstones in regular sized gravel tanks release bubbles, and they find their way out of the rocks, but sand holds the bubbled back

[Drumachine09]

I thought it was anaerobic (or was it aerobic) bacteria?

[cocoa_pleco]

could be that too. ive heard mixed stories about that bacteria and CO2 pockets

[niqolas619]

if you have regular gravel now, youre okay. what builds up in sand tanks is CO2 pockets, deadly. airstones in regular sized gravel tanks release bubbles, and they find their way out of the rocks, but sand holds the bubbled back


Nah, man, I'm talking about stuff getting stuck underneath rockwork, not the substrate. I understand the difference between gravel and sand, I'm sayin what about the bubbles that get trapped underneath the rocks.

[bscman]

I thought it was anaerobic (or was it aerobic) bacteria?

+1 ... I've heard of these "pockets" turning the sand black in those area's as well. Quite toxic to your fish.

The best bet for sand is to use only a THIN layer, or rake through it when you do your water changes.

[GoldLenny]

The anerobic pockets can form in compacted sand substrates and the anerobic (without oxygen) bacteria release nitrogen gas and hydrogen sulphide gas, both of which are toxic to fish. If you stir your sand bed more frequently (with your fingers or the handle of your fish net or any other type tool) or get some MTS (Malaysian Trumpet Snails) which will burrow through your sand bed looking for food and keep it from becoming a problem.

[Dave-id]

I just thought I should clarify, Nitrogen gas is not toxic, it's only the H2S that is poisonous.

The air pockets that accumulate in your ornaments are nothing to be worried about though, they're just air. Even if they stay trapped under your ornament for a long time, there's no way for them to go bad since they're also exposed to water.

It's only when toxic gasses are being produced in compacted sand, and they cannot get out; and so the bubble grows and grows until eventually it's large enough to break through the sand. Then all of the gas is released at once.

[Fishguy2727]

And it is not even anaerobic, it has to be anoxic. Denitrifying bacteria that breakdown nitrate into nitrogen gas are anaerobic. The hydrogen sulfide producing bacteria are anoxic. Anaerobic means very little oxygen, anoxic means none, that is why it is black. This is a big issue in saltwater aquariums, especially in the debates as to what is best, shallow sand, deep sand beds, or plenums.

I keep the sand in my tanks shallow. I do not stir it though. I am not on saltwater forums much, but in freshwater ones I have never had anyone come on and say anything to the effect of toxic gas bubbles were causing problems. However, most freshwater people don't use sand.