if you buy a 400w hps ballast you can run your mh light in it. but if you buy a 400w mh ballast you cant run a hps in it.
mobay Reviewed by mobay on . Quick Lighting Question, Please Help!! Ok Im New Here but i been doing my research for a while and seen all the different lighting options for veg growth as well as Flowering Stage. I've Decided to go with H.I.D. but like most people im looking for the best buy in Dual MH / HPS 400W. I Seen that they make Conversion Bulbs like a MH conversion bulb that works in a HPS Ballast and Vise Versa, I will be growing 4-5 plants and wanted to know if it makes a difference in whitch should be my primary light if i get the conversion bulb? I Rating: 5