I've supplemented my 250watt HPS bulb with a T5 Fluorescent ballast w/ 4 24 watt tubes for side lighting. When these girls get taller, they will need some extra light to their undersides. When the canopy gets filled, I will need it. I had that problem with my AK47 last grow, I could have had bigger secondary buds lower down on the plant if their was more light there.