Originally Posted by mr_X
I'm currently using a T5 fixture right now that puts out as much lumens and PAR as a 400 watt halide, but spans a 4' area. I don't see how that could be called moderate lighting.
In the general scheme of things, I consider the T5's to be fine for almost all corals if the fixture is matched to the tank depth. But not all T5's are made equal, or bulbs, like any other lighting source. I don't think they penetrate as well as MH
or LEDs in most set ups.
That's why I class them as a "moderate" light source. JIMO