anerobic pockets in my 2inch sandbed?

[William]

I've got some black pockets in my 2inch sand bed, and I can see some air bubbles forming in the sand in places. is it possible that this shallow bed is developing this?


I thought you had to have atleast 3 inches before anerobic was a risk..

 

[Anemoneman]

Black pockets are opportunistic cyanobacteria. Harmless. A good spot for it.

3 inches before anerobic was a risk..

I wouldn't call it a risk but rather a desired state of a DSB. I venture a guess that you are seeing some nitrification at the lower depths and that's the cause of the gas bubble. Certainly nothing to worry about.

 

[Brad]

anaerobic activity in sand

...I was going to say the same thing. If it is anaerobic activity...great! If it is only happening in small pockets...even better!

Even if not, it is likely a natural sand phenomenon, which is good. Just make sure you've got some critters that will occasionally dig it up and release it.

 

[fishfreek]

Where are you seing these black pockets? Is the black on the surface of the water or is this black on the side of the tank thru the glass?

 

[William]

Through the glass towards the bottom of the sand.