Fish do not require light, so an spectrum color you like works. I would recomend to go with split colors.
10k and Actinics. Also available in what they cal a 50/50 bulb if you want the combined colors both in same bulb.
10k is very bright and will light up a stadium, and the actinics will bring out the most colors in your fish and tank as a whole.
Good luck with the kelp as it is harder to grow than it looks but should do fine under any spectrum between (2,200k and 22,000k)