Its a comination of bryopsis algae and what is known as Calothrix. These species of cyano often appear as a light slimy yet hairy/fuzzy nastiness that loosely attaches to your rock work. Air bubbles are usually trapped while escaping the algae. Calothrix is a type of algae that looks very similar to Dinos.
A couple ways to get rid of it:
Manual Removal: Remove the rock and scrub, and then fine tune with a toothbrush. Let the cleaners get the rest. It helps to use a net to collect the debris that will occur as a result of the toothbrushing.
Afterwards, add Clean Up Crew: Chitons, Nerite and margarita snails and other cyano cleaners work well.
