Need help IDing something growing on my macro algae

[reddevilant]

About a month ago I bought this red titanophora algae and it's been doing great. However, recently there has been this whitish growth on it. Could any one ID this and let me know if I should be worried? To me it really resembles the color and texture of the lichen that can grow on trees so I was wondering if it is some type of fungus. It's brittle and will crumble if I touch it.

 

[Rtaylor]

Are you sure it’s not just detrius and sand?

 

[reddevilant]

Are you sure it’s not just detrius and sand?

Definitely not detritus unfortunately. I had cleared it off a while ago and moved the macro to a higher flow area thinking the same thing but it came back.