What is this on my LR

[sallen]

The attached pic is of some LR i am trying to cure. Can someone tell me what the white stuff is on the rock and what should be done about it PLEASE ???

 

[kogle]

The white stuff looks like it could be dead coraline algea. I wouldn't worry about it if that's what it is.

 

[am3gross]

dead coraline is what i thought also...... pic is kinda blurry tho.