Hi Stonepilot i don't know If you have a sponge out break or what??
But from My personall experiance I have a Pencil Urchin (Eucidaris tribuloides) that will eat all the Coralline algea and if the Live rock has a sponge on it that Urchin will eat it as well.
I have also been told and I can't remmeber what type, Species of Angel Fish feed on sponges you might reserch that as well Good luck ...Jeff
Check out the link:Feeds mainly on sponges and tunicates
I used to have a Koran Angel in my reef. He loved to eat sponges!!! And he would sometimes pick at "meaty" brain corals, and softies. Eventually he had to go. But if for some reason you want to get rid of sponges a Koran is a good choice.