well i have a ballast and u can get a bulb that can switch from MH to HPS so you only need one light. i plan on trying to make a stack in my 6foot tent so where i can veg some shoreline clones using hydroponics to do my sea of green setup. and for veg i will make a LED light setup to reduce heat and my watt output. im not sure yet but i think ill have enough room to use the top half of the tent to flower my clones using my current light.