Black sponge REEF2REEF Saltwater and Reef Aquarium Forum

I've been told this is black sponge. Do I remove it? Will it spread?

Is this a sponge? REEF2REEF Saltwater and Reef Aquarium Forum

Getting rid of encrusting sponge REEF2REEF Saltwater and Reef

Sponge? REEF2REEF Saltwater and Reef Aquarium Forum

The beautiful sponge REEF2REEF Saltwater and Reef Aquarium Forum

Pest Sponge REEF2REEF Saltwater and Reef Aquarium Forum

Black Encrusting sponge ID REEF2REEF Saltwater and Reef Aquarium

Black slug looking thing? REEF2REEF Saltwater and Reef Aquarium

Experts-What is this black stuff?

Sponges of our Tank REEF2REEF Saltwater and Reef Aquarium Forum

Black algae??? Need help! REEF2REEF Saltwater and Reef Aquarium