Black sand... now what?

[dirtyBit]

Lately I've been seeing more black areas about a 1/4 inch under my sand. The top layer of sand is a little harder than the rest which I think caused an anoxic layer to form. If this is the case what's the best course of action? I was doing a water change (getting rid of a little cyano) and then I saw some black sand. I syphoned it as best I could and tried covering up what was left. I keep hearing conflicting info on this. Do I "gently" stir the sand? Do I never disturb it? I have a few nassarius snails but they only seem to burrow in the same places while leaving other areas untouched. How should I proceed?


Info:
4-5" sand bed, about 10 months old. 90g DT, 30g sump.

 

[fishhead79]

Can you provide a pic?

Changing the flow could assist with eliminating it.

 

[frinzy1]

The live sand works as a filter catching all the nitrates and other things in your water. If you stir up the black sand in your water you can raise phosphate and nitrate levels in your water. I was told not to disturb the sand.

 

[dirtyBit]

I've never "disturbed" my sand and I think as a result the top layer has because firm (plus I think this may be a side effect of dosing carbon). This is not allowing air to get underneath this layer and causing a toxic buildup. I don't know if I should just leave it alone or slowly siphon it out. I siphoned it last time I saw it and have not had any ill affects yet so I think I my continue doing so until it's gone. Thanks for the responses.

 

[frinzy1]

Do you have a sand sifter? Either a Goby or a sand sifting star?

 

[maxx56dog]

sounds like hydrogen sulfate, possibly a sand sifting goby could help aerate the sand better.

 

[ldallen95219]

I stir/blow my sand about twice a week. I either use a turkey baster or use a plastic fork and just go over the top of the sand. Just stir only the top part of the sand - do not go down very far. I have never had any problems with my readings by doing this.

 

[Playa-1]

The problem is that the black sand could be trapping hydrogen sulfide gas which, if disturbed could rapidly cause serious issues in the tank, likely resulting in a tank crash. It would be a big gamble just trying to suck it out. Stirring or siphoning the sand bed is all fine and everything but it's before your get the toxic buildup. It's a different story once the buildup is there. It's the big reason people refrain from using DSB in the DT these days. Lots of crashed tanks from disturbing toxic gas. It's not a huge issue if it's in a remote sump where nothing is likely to disturb it. That is why you see more RDSB's, but in the DT you can bet something will disturb it at some point. Unfortunately, I don't know of a safe way to remove it other then pulling your livestock during the process.

To give you an idea, I had a small pocket of that stuff build up in a piece of hose that was lazily left in my sump. One day I pulled it out and about 2 seconds later my controller alarm went off. I smelled the sulfur smell near the sump and unplugged the return pump so as not to pump that crap into the DT. The ORP meter in the sump had dropped to almost 0 in just a couple of seconds. I think the controller saved my arse that day