I have a current usa orbit set up above my 29 and the 67k-10k light it came with was just too yellow for my taste. I switched to a straight 10k and the color with the standard 71k-03actinic gives off a nice crisp white light with a slightly blue tinge. I can tell by the growth of everything in my tank since , their enjoying it too. Frogspawns are splitting on 2 heads, accelerated growth of zoo's, and much better extension on torch and my derasa. Coraline has improved too and nuisence algea has gone. I'm thinking about changing the actinic bulbs to something else. Has anyone else tried other combinations in this unit? Curious, Curtis