Zoanthids browning out? Identify algae please, pic inside

[socalnative]

What is it?
I closed all the zoa's so you could get a good view of the slime. Ill post a macro pic if you need it.

Any suggestions as to how I can treat it is appreciated.

 

[JGoslee]

You can gently scrub it off with a toothbrush or pull it off with tweezers. If its Nuisance algae the best way to treat it is to lower nitrates and phosphates.