Coralline algae and something white?

[Jedi Knghit]

My tank is about 8 weeks old. Is it possible to have a spot of coralline algae already? Also, I have an unusual white post on one one rock in the middle of a bunch of green algae. I am positive that this part of the rock was covered in green algae a few days ago. Any idea what it may be?

 

[James M]

That is Coraline algae and it just looks like that white part hasn’t been covered with algae