Fiji live rock with black surface

[barchtruong]

I just bought some liverock from a guy who ended the hobby. The rocks have alot of purple coralline algae on them, but because he didn't take good care of the tank, those areas without the purple algae turned into deep green, almost black. I used a tooth brush but it didn't come out. Is it permanent or will it go away in time as I keep the water quality hi? I have 120lb liverock in my current tank and my rocks are purple with white in some areas.
If you have any experiences with that situation, please share with me. Thanks.

 

[lion_crazz]

Sounds like it could be die off. I once left live rock in a bucket and forgot to put a powerhead in the bucket. Well the rock turned black and smelled ATROCIOUS. How does the rock smell? Is the smell tolerable?

 

[barchtruong]

thanks lion for your comments.
Well his tank sure was dirty. Not only the rock turned black, the gravel did too.
When I brought the rock home, I took some of his tank's water home with me, so the rock are still "live"

I suppose. But I could smell a kinda funny smell coming out from the water and the rock. It's not a rotting smell. It smells like grassy or muddy sorta. There are so many thousand legs worms in those rock and they crawl out even I have the light on. There are a whole bunch of tiny feather dusters growing on the rock. I've noticed that alot of those dark green stuff has coming off and settled to the bottom of my temporary tank. I really hope those black surface will come off or they sure look ugly. Thanks.

 

[natclanwy]

Not sure if it is die off or not, dying rock smells horrible similar to the collection cup on a skimmer. The dark areas should eventually be covered with coraline again may take some time though.

 

[unleashed]

sounds like coraline algae lacked lighting and turned dark if its not smelling awful it should be safe all the life in his tank is also a very good sign

 

[barchtruong]

thank you,
a friend of mine bought a sw tank from someone else about a year or so ago and he had no clue whatsoever about sw world and he never bother asked me how to care for the tank. He bought the whole setup basically cuz he thought the whole thing was cheap..

. But anyway, my point is my friend is as bad as the guy I bought the rock, and my friend's lr has the same blackness on the lr that I just got. So, it's weird. I've noticed some area has lightened up a lil bit, but not a whole lot. Hopefully, the worms will eat away all the black algae for me. Oh, speaking of worms, a big worms sneaked into the powerhead and got chopped in to pieces...ouch.....I feel pretty back cuz I like those good worms, but I can't stop them from crawling into the powerhead....