Not sure if you mean bulb combination or not, but I will assume you do. My recommendation is whatever colors you find most pleasing on the tank, likely Blue Plus and one other. Taking recommendations for bulb choices is a bit like taking recommendations for what color of car you should buy. While everyone has an opinion, ultimately its up to you what you want to look at. If it were me, I would probably do a Blue Plus and a Coral Plus since the Hydra 52 has Red LEDs and plenty of white (meaning, I would rule out the ABS and P+). It also has plenty of UV so the True Actinic isn't needed.