From the research I have done, LED's received a bad reputation with growth early on because people assumed that white and blue was all you needed.. Turns out royal blue is more in the coral growth spectrum and blue is not. From the people that I have talked to for my build advice, they are getting great growth using just royal blue and cool white. Different people, different ratios, but I do know 2 people, one guy is 1:1 and one is 2:1 rb:cw and both of them are having great growth