Tiny black spots on rocks. Coralline grows everywhere but rocks.

Deltec

pw9988

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Not sure what it is and I can't seem to find any info online. There's little black dots all over all my rocks and it's spreading to the skeleton of some of my corals. Added a small piece of rock in (to see if it will spread to it), and within 2 weeks or so the black dots spread to it as well. Not even sure if it's algae. For some reason, coralline refuses to grow on my rocks, but doesn't seem to have an issue anywhere else, including the glass, the pumps, etc. The rocks are Marcorocks from BRS. The black stuff doesn't appear to encrust or connect together to form a "covering".

Maybe #reefsquad have seen this before?

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vetteguy53081

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Looks like a type of black sponge. As long as you have rock in your hand, remove and scrub black areas with a firm toothbrush and hydrogen peroxide
 
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pw9988

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My only problem with that is it's over all or most of the rocks now. I'd have to remove everything and scrub it down. I don't suppose there's a chemical solution, right?
 

Poof No Eyebrows

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Looks to be algae covering the rock (the green). I would scrub that off. I don’t think coralline will grow where there is algae already present. So clean up rock and then help kickstart by scrubbing some of your coralline in the tank to get it in the water column and seeding the cleaned rock.
 
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Deltec

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MrReefs
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