Evil black funk in the sand

[loconorc]

Wow is it that dangerous? So do you guys stir up the sand constantly? Cause Ive honestly never heard of doing that and I have done my fair share of research...

If the sand turns gray can it go back to being white if the bacteria are dead, or is it permanent?

 

[loconorc]

What does this stuff do, exactly?

 

[Pufferpunk]

anaerobic
"Without air". Refers to an area with no dissolved oxygen - these can build in pockets between rock without adequate circulation, or under fine grained substrates unless you have a burrowing organism to stir it up. Anaerobic bacteria are cultivated in some types of systems like deep sand beds, because they are able to convert nitrates into harmless nitrogen gas. However, in most systems anaerobic bacteria are not desirable; they produce hydrogen sulfide and other toxins.