digi= digital ballast, weighs less, runs cooler, and will light either MH or HPS bulbs. Before I went all the way using HPS or MH, I would veg with some cool white CFL and flower under HPS.

Or, you can buy conversion bulbs that means a MH bulb will run on a HPS ballast and vice versa. I dont know much about those, that is not the route I decided to go.

With light comes heat, and that is a serious issue you need to address also. If you need to keep your light 6' away from your plants to keep from cooking them you might as well grow with candles. You want the light(s) as close as you can possibly be (12-18") and your plants are not dropping dead. It can be done but ya gotta have the right setup. CFL's even closer than the 12-18"


b0nger