i got one 400w metal halide runnin on two plants soon to be 4 and they LOVE THIS LIGHT!!!! run HPS on flowering 400w would be all u need...or hell ive been hearing about the ceramic metal halides and they say that they r the new way to growing. use a 400w cmh for flower and veg!!! dont have to have two ballasts.. save some money.. and i would say they hell with flouros...use those for your clones or your starters...if u spend money now...its worth it after first harvest...shit i havent even reach my flower stage yet n these lights are the way to go compared to the cheap way...buddy of mine been doin sea of green with flouro on veg and hps on flower for over 8 years...thats the cheapest.. most efficient way to grow if u want to grow some good,dank,full,buds