It's really one of the biggest controversy out right now. CMH vs HPS . Half says having the heavy red spectrum is better for flower but then the other half argued the more efficient and usable light aspect despite much less red spectrum. It'll come down to one day when I decide to go that route. Although i have to say with all due respect of course , im by no means a pro at this stuff. But i think running a 400w hps with a 315cmh would be tits. Mixing lighting how benefited my grows here in the past and just imagine having half heavy red spectrum and half more usable light from the full spectrum would be ideal nay?