Do a bit of research....metalhalide is by far superior to hps for tric development and was the staple for growing for many years....ppl tend to like hps as it puts out more lumens per buck...for my best results I mix both as I have done for years, every time I try to mix it up with more (cheaper) hps and evan LED for a while my quality and or yield goes down....anyway it may be just me but after 25 years in this game ive seen many if not most scenarios...jmho!