"potato chip" ID

[NathanH]

I have this algae in my tank and I am wondering what it is. It obviously consumes a good deal of calcium as it has grown quite well. The whole "colony" measures 5"x4". Anyone have any idea of what this is???????

thanks

Nate

 

[Gary Majchrzak]

That's an easy one. I only needed your pic to confirm my suspicion: you have Padina .