My theory is that the light saturation point for algae...at least the pest algae...is pretty low. Once this has been met, and other conditions are right, it will grow whether you are using PC
's or the nuclear furnace in the sky. One of my prop tanks gets the morning sun through a window up till about noon. I don't have any algae problems with this tank. The other one, further in the room and not getting the sunlight, is giving me fits with hair algae right now
. Also, in reading Anthony Calfo's book about coral propagation, he says pretty much the same thing about sunlight and growth of pest algae. I would offer a direct quote, but my desk is piled up so badly right now that I can't find the book.
It's interesting to note also, that after a couple of hours of the sunlight hitting the tank, all the coral frags
that can are leaning towards it. Anyway, JMHO