they will not just grow over your coral, but kill the colony as well. If you like GSP, or use them for revenue at you LFS, then localize them on the sandbed/ starboard and put rocks next to them for culture! Or.. get a wire brush from your local golf store (used for cleaning clubs) and go to town scrapeing GSP off your liverocks. On a more personal note GSP are D&!* annoying.. its too bad women love them so much, huh?!?