Is this green hair algae?

[saltyfish24]

Sorry for yet another what is this algae, but I looked at GHA threads and I didn't think this was it...but I'm not sure. This is illuminated under white light.

I'm referring to the dark green or blue-green spider threads that are waving in current. They only grow off the sand, I don't see any on rocks. My urchin will eat them if it comes across them.

It's not bothering me. There's just a few patches, and they're not even on the brightest parts of the sand.

 

[Tinnerito]

Sorry for yet another what is this algae, but I looked at GHA threads and I didn't think this was it...but I'm not sure. This is illuminated under white light.

I'm referring to the dark green or blue-green spider threads that are waving in current. They only grow off the sand, I don't see any on rocks. My urchin will eat them if it comes across them.

It's not bothering me. There's just a few patches, and they're not even on the brightest parts of the sand.

It looks a little too slimey to be hair algae but I have a very similar case with a red variety, cyanobacteria. It started in a small amount; didn't bother me but trust me once it establishes it grows fast. I'd try target removing some of it now just to be safe.

 

[ReefRigger1]

Ew... I actually don't know what that is. But, doesn't look like green hair. A little too dark, thin and I have no idea why it is coming out from the sand. If you have something you use to remove things from the saltwater tank, maybe try picking at it.