Sponge ID? Or cyano

[Robjrussell]

Hey all,

Returning reef keeper after a decade plus. Trying to figure out if this is sponge or cyano? I am leaning toward sponge as from the side it looks like it is a little bit grown off the rock.

Any ideas?

Cheers

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[Sugar Magnolia]

Have you touched it? Try brushing it off.

 

[Robjrussell]

I haven't touched it. If I brush it off would that be bad for rest of tank if it's cyano?

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[Sugar Magnolia]

Just use some airline tubing to syphon it out. It does look like cyano.