How did you acclimate the tank/corals to the new light? Have you tried moving them to a lower/semi-shaded portion of the tank? That's quite a bump in light intensity -- when you first got the PC
's, did you start at a lessened photoperiod and slowly increase it from there? Make sure they get good current/water movement -- star polyps always retract when any kind of detritus settles on them. You might want to try gently blowing them off with a turkey baster.
Not sure about the "blob". Could be a sponge, or possibly a tunicate (sea squirt). Any pic might be helpful.