[Myka]

Yes, Lobophora has an encrusting type too. The main difference is the filaments are only on the outside edges of the Lobophora and Pseudolithoderma has the filaments all over. The filaments should be more like 3-5 mm long, and very, very fine. These are feeding filaments though, so the algae have the ability to retract the filaments. As mentioned above, when looking for pics of Pseudolithoderma, look up Ralfsia instead as you'll find many more pics.

If it is Lobophora, I would be trying to remove it. If it is Pseudolithoderma (Ralfsia), I wouldn't bother messing with it.