I not concerned about PAR really, the Iwasaki 175w 15k bleached ALL of my corals, even millis, for some reason my corals hated that bulb. I slapped a 20k 250w in there (XM), that has less PAR, and my tank thrived. I'm not yet convinced PAR is an accurate way to determine how good a bulb is.... I just look at the color, and the coral and algae growth to make my determination, I try not to get caught up in the rest of the stuff.