From another thread, might help "Mounting you'll want the light anywhere from 4 to 8" off the waters surface depended on your fuge size on the grow setting, which will put out your red and blue spectrum for chlorophyll A and B"
I would assume you'd want it on the "Grow" setting for a fuge? I just setup a Kessil H160 on mine and that's what I have it set at, full intensity on "Grow".