Need Help identifying

[Tangdora]

Hi all. Posting this for a friend. Not able to even identify my self. He has a 250 gallon fish only fake coral insert set. It is being taken over by this dark algea algea like substance. It color is like that of a dark skimate but has the property’s of coralline. Attached a view photos and videos. It does not simply rub off any of the component or inserts but does easily come off scraping with a finger nail.

 

[BairCorals]

Same stuff that grows on your glass, it's on my clip as well. Not sure what the name of the algea or anything but I know it's just normal growth. Wouldn't be a bad idea to add some cuc of some sort

 

[Tangdora]

Actually was given wrong info. His main concern was just just dark blackish stuff that seem to be consuming the base of his inserts and seem to favor. Lower lighting as it does not appear to grow higher up.

 

[Reefkeepers Archive]

Actually was given wrong info. His main concern was just just dark blackish stuff that seem to be consuming the base of his inserts and seem to favor. Lower lighting as it does not appear to grow higher up.

Well that's what you get with inserts, algae will grow. Looks to be calcareous algae of some sort, which as you noted, is the same group coraline algae is in