Reef Rock Turned Black

[JSM]

I purchased reef rock from live aquaria and after a few weeks in the tank it turned black. No ammonia spike and all parameters were where they should be. I do dose vodka but never had this happen with real live rock. It doesn't brush off easily either and taking out to boil is not an option as there are corals growing on it. Anyone have this issue? Anything I can do?
Thanks,
Janna

 

[Mache62]

I bought some from a LFS and had the same issue...took it all out and put in in the sump. Now it's back to white again after no light for a month.

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[bertoni]

That's a bit odd. It does brush off, though? I'd guess you're seeing some sort of microbial bloom. It might go away on its own. How long has it been this color?

 

[Mache62]

Yea I thought it odd as well. I bought it and had it in my sump for a couple months before rescaping my tank....a lot of it was shelf rock. About a week after being in the lighted DT it started to turn...I figured it was a bloom and would go away. It just seemed to get more black though. I took it out and put it back in the sump where it promptly turned white again. Weird..

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[JSM]

It doesn't brush off easily. It's the reef rock that's pink all the way through. The bottom side is still pink so it must be the light. I dose vodka so nutrients are very low so what's feeding it, whatever IT is? It's been this way for 9 months, not getting any better. Some of the smaller pieces I've flipped over and within a couple weeks the pink is black again. It's so ugly, never had this problem with real live rock but can't buy that anymore so I'm at a loss. I've been in this hobby 21 years and this is making me rethink staying in because the rock is so ugly. Spent 100's of dollars for black rock!

Janna

 

[griss]

A shot in the dark, but maybe iron in the rocks?

https://blog.nationalgeographic.org/2011/09/01/black-reefs-when-the-ship-hits-the-reef/

 

[Michael Hoaster]

Live rock is still available from Florida. gulfliverock.com is one source.

 

[coralcruze2020]

this is strange... there is a black sponge out there thay grown on rock... might it be that? any chance you could post a pic?