In spite of what you think youve heard or read, all MJ cares about is total lumens and the light cycle.Yes research shows in the real world plants follow the natural progression of germinating, sprouting, and vegging under natural blue spectrum light.Later as they mature and the light spec shifts to red and then the cycle changes to 12/12 and flowering proceeds.This is the natural progression.However, you can produce good bud under total blue spec,or total red. Some prefer a combination.As a professional in the field of science you learn how to interpret information.Combined with 25+ yrs of growing, I know the effects of MH vs HPS is minimal in respect to the amount of lumens and the light cycle.Sweeping generalities rarely hold up.-usdi Agaluga