Here's a picture of my anaerobic (nitrate-eating) bacteria


Drug Enthusiast
This was an accidental experiment. I funneled some used, dry sand into a 2-litre bottle so it would be easy to rinse off (fill with water, cap, invert, pour out, repeat). I was going to use this sand in my little 15g tank but after I filled it with water I set it aside and forgot about it. Here we are, a month later, with a clear zone of black H2S product of anaerobic bacteria, as organics present in the sand were processed.

It's a fun illustration of how anaerobic bacteria works deep in the sand bed to process nitrates. However, it should not be contrived to imply that this bacteria is working at 1.5 inches deep in your aquarium. It must be taken into account that there is a lot of water flowing through the sand bed in your aquarium, thus your anaerobic area will be considerably deeper in your sand bed (if your sand bed's deep enough).

It's still fun though.



New member
A SSB(Shallow Sand Bed) of about 2" will contain anaerobic bacteria and will reduce nitrates, however more care must be taken as not to disturb the bacteria.


New member
Look at you and your Winogradsky column :)

That's really neat, even if I am biased as a bacteriologist ;)


New member
<a href=showthread.php?s=&postid=14782740#post14782740 target=_blank>Originally posted</a> by Anemonebuff
however more care must be taken as not to disturb the bacteria.

does that mean you should not vaccum the sand bed from time to time?


New member
I've found a dark ashy looking layer of sand in my < 2" sand bed, it looks similar to what you're showing. Is this anerobic bacteria or something else? When it's surfaced it seems to return to white sand within a day or two which would lead me to believe it's bacteria rather than sediment, but that's all I'm going off of.

Is the dark looking sand specific to anerobic bacteria?