Dangerous Bubbles?

[Drewbis]

I recently switched a 15g tank to sand and over the course of about 3 weeks algae had slowly started growing. I looked at the sand today and saw that underneath a small layer of sand there were bubbles that formed. I only saw them on the sunny side of the tank (where the sand touches the glass, of course). I have no reason to believe the bubbles are anywhere else. Are these bubbles a problem? I've been told if they escape and float up my fish will die (I have 2 dwarf puffers and a pleco in ther). Was he right?

 

[ashdavid]

How thick is your substrate? It could possibly be just algae releasing oxygen, but there are other explanations like gas biuld up from decomposition in anerobic conditions. This is nothing really to be concerned about because it is in such small amounts. If you are concerned just run a gravel vac around the spots regularly and if any get into the water column don't be concerned it wont kill your fish in small amounts.

 

[Dangerdoll]

If the are anaerobic pockets, they are something to be concerned about. As Ashdavid says though, run the vaccuum over them and try to keep thte bubble into the vaccuum (preferably a python). I can't be sure if they are just simple air pockets that formed from the gravel transfer but just to be sure, I would get rid of them. Anaerobic is nothing to be reckoned with, I lost a tankful because of it.

 

[jaylin]

I'd be a little concerned. Bubbles in the substrate normally aren't a good thing ... unless your looking for clams.

I don't know all that much about dwarf puffers, but is there anything you can keep in the tank with them that will stir that sand up or is any kind of maintenance crew just going to end up being pufferchow?

 

[mooman]

I think its probably just air bubbles from the algea, but trumpet snails will keep the sand stirred up and keep anaerobic pockets from forming. I know puffers eat snails, but trumpet snails have unbelievably hard shells, they might not be eaten. maybe someone else can confirm or deny.

 

[RTR]

MTS are as oxygen-limited as any fish, and do not, repeat, do not dig into anoxic areas of the substrate. Yes, they do spend time fully buried in the substrate, but not below the oxygenated layers.

 

[Drewbis]

The substrate is about an inch and a half thick.. Anerobic conditions maybe, but Oxygen release from photosynthesis probably makes the most sense, there is nothing decomposting in them that's for sure... I should have thought of that before, I spent all summer researching plants... haha. Ask me anything about Buckthorn and I'll give an answer. Anyways, thanks for the responses.

 

[f8ldzz]

Are these bubbles a problem? I've been told if they escape and float up my fish will die (I have 2 dwarf puffers and a pleco in ther). Was he right?

Is that a serious question???

 

[maaltan]

I dont understand why the substrate bubbles are super toxic. if it is in a oxygen deprived area then yes those bubbles could contain hydrogen sulfide and lots of CO2. But how would releasing them nuke a tank?

Wouldn't it be like the bubble wands. looks pretty does almost nothing. like .01% of the air pumped through those things gets dissolved into the water. In fact it will remove more CO2 than dissolve oxygen.

a few bubbles that rise up would pop into the atmosphere before any apprecible amounts got disolved into the water.

I would assume the bubbles would be more than an indicator of a problem rather than creeping death.

You said it was on the sunny side of tank. Is there algae growing in or near that pocket? if so I would lean toward it being a pocket of rich Oxygen. you could always pierce it with a piece of tubing while sniffing the top. if your eyes water and you gag its probably a bad bubble.

 

[RTR]

There is a difference in solubility of the gases being discussed. Even undisturbed anoxic areas are relatively harmless while undisturbed, but there can be some diffusion of toxic materials into the water column, and greatest risk is to the substrate dwellers. Disturbing an axoxic and H2S-loaded area can wipe out much of a tank. Such does get reported here periodically. Consider it a time bomb, and as such not a good thing to have in your tank.

But I do agree that the bubbles seen in the original post are more likely O2.