Hi Tinytoon,
Iâ??m using a cool tubed 400W HPS light. Iâ??m not sure about the manufacturer of bulb as Iâ??m borrowing the light from a friend. Itâ??s nothing special though since he told me it was a generic HPS light. I have the light about 18 â?? 20 inches above the plants. I can hold my hand on top of the plants without discomfort.