Is this Cyano?

update:

Well, I changed more things at once than I should have if i wanted to learn anything, but it seems to have worked.

Brain skeleton went bye-bye. Will probably just toss it, no longer desire a dead brain in my tank anyways. A live one will look much better later on.
Set the vortech to lagoon mode instead of crested reef mode. Lowered over all power a bit, but higher sustained flow.
Added a few cerith snails. they mostly ignore it I think, sticking to the walls.
Lowered water temp from 79.5-80 to 78.3-78.8.

Result is that all the purplish powdery stuff has since turned brown or disappeared entirely. Skimmer went nuts for a few days. Not sure what change did the most.

water params have been stable since before i noticed anything, everything that should be trace or lower is.

Whatever it was, it's mostly gone now. I am getting good coralline growth now, all my rocks are turning deep purple and lime green.