Generally, reefers dosing carbon can get a white stringy bacteria growing on rocks and such. I dont believe this is it.
Looks more like Chrysophytes. It derives from silicates or water quality issue.
My best guess is Calothrix. This 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 eascaping the algae. Calothrix is a type of blue green algae that looks very similar to Dinos. To battle this:
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.
Starving it out:
Use a phosban reactor or a macro like chaeto to take down phosphate. If you have a nitrate problem too, you can add more live rock or rubble to the tank, do some more water changes, or add macro.
Clean Up Crew:
Add Chitons, and Nerite snails who will take this down as well as some blue hermit crabs.