I have about 4 different varities of sponges growing extremely well in my tank. With 2 Goldens, 3 Venustus, 2 MultiBar, a multicolor, a flame, 2 flamebacks, a bellus, a gold flake and a red sea regal the sponges are growing at a faster rate than they are being consumed.
Several of the sponges have started growing from out of the darkness and into the open water, and I don't see any nibbling of significance going on.
Dave B