Help! Algae problem..

[akaimal]

I first noticed this algae in my tank a couple of months ago.Few weeks ago I noticed that its growing aggressively on rocks where the flow is high. Its growing in two ways: encrusting the rock and plating.

I was able to easily remove the plates. But its hard to remove the encrusting part manually. What can I use for getting rid of this algae?

nitrate and phosphate are zero.

 

[Gdevine]

Looks like Cyno to me.

 

[OwenInAZ]

Cyanobacteria don't plate.

Orange coraline? I've heard of orange stuff before, not sure how common it is.