I've got 16 3w crees (9 blues/7 whites) with no optics over my 29 biocube. The PAR measures 650! I currently am only running the LEDs at 20% which is a lot more (220) than my old 150 watt halide was providing (60). For comparison, a 14k 150 watt halide was about 340 when new.

My guess is that a lot of people without access to a PAR meter, smoke their corals under LEDs.

As I mentioned rob, I have the dimmer pieces parts that came with the DIY fixture I bought that you can have. It includes a 12 volt transformer which is used to power the dimming circuit....although as I understand it, a 10 volt is what you really want. Having seen one of these now, I can see how easy they are to put together.