That is my bet...an encrusting sponge!
As for the algae, their were probably excess nutrients in the pet shops tank where you got the live rock, or a lighting issue!
Tangs, snails, crabs etc. should help to keep it under wraps as well as good water conditions! _________ 125gal.w/Mag9.5 return(dual megaflow)>Mag7 pump Aqua Cev180skimmer.Wave2k Hamilton Reefstar(2)250watthqi(mh)pend.a Yellow, Naso Tang Red Lip Blenny Percula Clown Demoiselles Niger Trigger F. Wrasses Ceriantharia Orn.Shrimp and Stars Hermits Queen Conch asst. snails> Stars Zoos shrooms Montipora Brains Gorgonians Favia Turbinaria(large+small polyp) Acropora Xenia Tridacna (CroceaMaximaSquamosa) Leathers <35+75gal.reef tank as well>
"IF THE PHONE DOESN'T RING...IT'S ME"  jb |