It has to reduce par... For most it may not matter because they do not run 100 percent anyway. Still do not know why some company has not tried using led indirect. In the commercial industry that is how they get around leds being so much point source. I know I have been specing more led fixtures since they have been going indirect.
A reflector would most likely give better control and less light loss instead of using a lens and scramble the light. Anyway do not want to hijack Gregs thread.
Of course it reduces PAR -- My mistake if I typo'd and made it sound like it doesn't.
The question is -- Whose running their
G4 radions 8-10" off the water (where the diffuser is designed to be) at 100%? G3's are no joke.. But as far as power goes, they aren't even in the same league. I've not seen anybody run
G4 Radions over 65% without starting to kill everything.
For G3 -- Yep, you will lose SOME par, for sure. But par in and of itself isn't the end all be all anyways. Most people running G3's also don't get much higher than 80%, they additionally run these G3's MUCH higher off the water surface (12-16"+). So the par from lowering the lighting fixture alone is increased significantly, even with the loss from the diffuser.
BRS had a video about light height and par loss with the xr30 G4 -- I believe 2" made a difference of just over 10% par.
So with that in mind, I ran my XR30 G4 14" over the water at 55% (where corals started bleaching), I put on the diffuser, losing 20% par, then lowered the fixture 5", potentially gaining 40-50% par, with the diffuser around 20-30% par -- My light had to be turned down to 50%, it's putting out 72w of power with WWC's color program (modified AB+)
I do agree that reflectors have a place with LED's. Inside of the diffuser it has non-metal reflectors. White is highly reflective, matte/flat white especially, which is why all movie theater screens are a matte white. Inside the lense are matte white reflectors. I forget the number, but pretending that a silver reflector is 100% reflective (it's not) a matte white is somewhere around 95%+, which is pretty good. So inside the diffuser IS a reflector, and then a diffuser.
My second favorite motto in reefing; "It's always more complicated -- Always"
