Can someone ID theese brown disk things growing on my sun coral

[Isaac85]

 

[JUNBUG361]

Rhodophyte/Red Algae Maybe

 

[Sugar Magnolia]

Padina algae. http://www.saltcorner.com/AquariumLibrary/browsespecies.php

 

[A sea K]

lobophora variegata is what it looks like to me. If you can positively make this an ID then GET IT OUT! The stuff grows like a plaque and the only thing I know of that will eat it is a Naso Tang.

 

[Isaac85]

i think you are correct looks like lobophora variegata. will it kill my sun coral? or any other corals?

 

[A sea K]

Not that I am aware other than overtaking and smothering it. I had it in my system and it was a fast grower and impossible to eradicate by manual removal. My tank at the time was large enough (210gal) and my research suggested a Naso tang as one of the few things that would eat this particular algae. As I remember another suggestion was a Sally Lightfoot crab of which I added several to no avail. When I tried the Naso he immediately began feeding on the Lobophora and completely eliminated it within a month.
If you have a smaller QT tank I would move the sun coral to that system till you can manage to get rid of the algae before it spreads in your display. It appears to be isolated to that coral and will be easier to deal with. I dont know if a peroxide dip will harm the sun coral but that is a possibility after some aggressive manual removal.