I run hps mini systems on my fuge. Cheap, little heat and grows like mad.
To answer the question, pretty effectively, the lower the kelvin, the better in my experience(i know that goes against the thinking, but it's very effective on the reef end). But also, plenty of power is needed to grow it fast and effectively. In my opinion, most of the fuge that will not grow, is basically because of lack of light power.
I clean my fuge out at least 35% every two weeks at least with the sodium. Before that, with a little led, it was dying. I also have run full 165 watt led fixtures, with both channels on, one dominant, etc, and the sodiums just blow everything away..