at least 3 actinics, 1 75/25 and 2 10K, that gives you good color in coral but you have a white light color on the tank. 4 actinics and 2 10Ks will probably give you a 12K-14K look. or 4 actinic, 1 75/25 and 1 10K for a 15-20K look. This depends on the bulb brand. I use geismann(sp) for actinic and UVL for 10K's. Geismann's 75/25 which pefectly matchs UVL's bulb is aquablue+ so either will give you the same color.