About the only thing beneficial to MH lighting is the transition from veg to bloom triggers preflowers faster. It vegges slower, and is useless in Bloom. I use Horilux red bulbs throughout veg & bloom. 20K more lumens makes for fast vegging. 36 hours of darkness between 12/12 will pre flower em out as fast as switching out MH to HPS. MH belongs in a stadium. a Football or baseball stadium!