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 sponge good or bad?? REEF2REEF Saltwater and Reef

Sponge ok to have? REEF2REEF Saltwater and Reef Aquarium Forum

Weird curly black things growing REEF2REEF Saltwater and Reef

Black sponges? REEF2REEF Saltwater and Reef Aquarium Forum

Black sponge? REEF2REEF Saltwater and Reef Aquarium Forum

Hello - Sand turns black, Page 2

Black sponge REEF2REEF Saltwater and Reef Aquarium Forum

What is this thing??? Help a noob.

Black sponge killing GSP? REEF2REEF Saltwater and Reef Aquarium