In my quest to hunt nuisance crabs...

[peacemaker]

I spotted a nuisance crab this afternoon, and as usual, no mercy, managed to grab it out of the tank with my tweezers.

[peacemaker]

In order to get a good space to get to him, I needed to lift a mushroom rock. I was quite shocked to see this...

[peacemaker]

My live rock is turning black at the bottom. Anyone knows what is this? I read somewhere about some kind of reaction underneath the sandbed, but I do not know the details. I have seen this before, and it is very difficult to remove even with scrubbing. Any effective way to get rid of it?

[peacemaker]

More than prepared to do a major "overhaul" of the tank to clear this problem. Is this also one of the reasons why some folks here go bare bottom? Pls help?

[peacemaker]

Anyone knows the root cause of this situation?

[BarraCudaTM]

Anyone knows the root cause of this situation?

Typical anaerobic zones will cause liverocks or sand to turn black, I wouldnt be too bothered about it.

[peacemaker]

So do you mean it is harmless? Can I leave it as it is or try to scrub it off? I checked on it this morning, and it seems like it can peel off like a sheet of tissue paper.

[BarraCudaTM]

So do you mean it is harmless? Can I leave it as it is or try to scrub it off? I checked on it this morning, and it seems like it can peel off like a sheet of tissue paper.

Up to you but I would just leave it alone.

[peacemaker]

Thanks for your reply! Will continue to monitor the situation.

[LaW]

it might be metal sulfide. happens when theres low flow. but most of the time it can be found when you break open your rocks into 2. so im not too sure on that as well. but will just try to monitor it.

happy reefing.