Weird algae

[maksim serebro]

Hi, got this weird green/blue algae growing on sand and in the sump.

Tank is about 6 months old. Nitrates and phosphates test 0. Filtration is with skimmer and ATS. I have some cyano but it’s the normal red color. This stuff is strongly and blue/ green. Any light on the subject would be appreciated. Corals seem unaffected

 

[Bleigh]

It kind of looks like arm hair. Is it hair algae? I'm too new to the hobby know of anything else it might could be.

 

[maksim serebro]

Definitely not regular hair algae. Breaks up easily.

 

[reef lover]

Cyano comes in green and a bluish purple.