Its intensity, not wpg. I could put 1000watts of flourc. and it still wouln't be the same as 500watt of MH. aren't corcea's supposed to be on the rocks, hence the foot that is grasping for the rock. Squamosa would be great on the sand bed. I have both and enjoy the difference in blue,green, and brownish/pinkish of squa. I think if you try a corcea under PC's or T5's place high on the LR, as stated earlier and look at 7-8wpg. OR JUST GO MH,lol.