I've ran metal halides alone, t5 alone and kessils alone. My best success came from T5's. I just did 7 months with Kessil 360we fixtures and got excellent color but little to no growth. I wanted them to work well because they were efficient, sleek, and made great shimmer. Unfortunately they just didn't produce. I went with a 6 bulb Geissman and 2 reef brites. In ust a few weeks I got noticible growth and color pop again. Im sticking with T5s for now !