Is this an algae?

[Hector Fajardo]

hello, I recently bought this rock for my reef tank, it has some type of algae on it. It’s leather like and can’t be removed. Any ideas on what is it?

 

[James M]

Looks like Cyano

 

[Florida Sunshine]

Looks like Cyano, I agree, but what he is describing is not Cyano. Leather like and cannot be removed.
How have you tried to remove it? Pointing a power head at it? Trying to pull it off with your fingers or trying a scrub brush etc.

 

[Hector Fajardo]

Looks like Cyano, I agree, but what he is describing is not Cyano. Leather like and cannot be removed.
How have you tried to remove it? Pointing a power head at it? Trying to pull it off with your fingers or trying a scrub brush etc.

It has a power head on it, and yes I tried to brush it off. It is thick, slippery but not soft.

 

[Leo58]

It is some kind of algae, I have it on one of my rock. It's a slow growing type but can spread to adjacent rocks

 

[Brad Miller]

Looks like driftwood to me....you sure you bought real rock ?;Happy

 

[Florida Sunshine]

I would try to remove it. Even if I had to do it bit by bit.
I can't really say why since I don't know what it is but that is just what my gut says.

 

[Jon Fishman]

how close-up of a picture is that? Thumb sized section on a 20 lb rock? Looks almost like calcium build-up