algae id request -- all input appreciated

[FartyParty]

This stuff is growning anywhere there is bright light and starting to choke out some of my coral plugs. It does not grow in my overflow box, which is pretty dark. It seems to prefer to grow near or on corals, but is on the rocks as well. It seems more soft and slimy than hair algae. Any ideas what it might be?

Stats just taken an hour ago:
Dkh = 8.5 (hanna colorimeter marine dkh)
Mag = 1480
Cal = 1420
P04 = 0.00 (hanna colorimeter low test, not ultra low test)
N02 = 0
N03 = 0
Ammonia = 0

All non hanna tests were taken via red sea test kits. Tank is 16 months old and no fish deaths since inception, but some coral deaths due to bleaching.

 

[saltyfilmfolks]

I’d its cottony to the touch with some structure and not slimey(a bacteria ), most likely a chrysophte or diatom.

Odd to see in an older tank.