The T-5HO or T-5H (same fluorescent tube) in a 4 or 6 tube fixture is a really bright light, the brightest lights I have ever had. I have six-tube fixtures and use 4, 6500K and 2, 4000K tubes in each fixture. That gives me a broad growing/flowering spectrum. If you are used to "cool" fluorescent tubes, not "cool" spectrum, but "cool" to the touch, beware. The T-5HO tubes get really hot. I started out at 6", quickly moved them to 12", and finally moved them 18-24" away from the plants. The tubes were actually sun burning the leaves of my orchids. Plumeria can take more light/more heat, but still watch what's going on at the leaf-level if you go with these fixtures.
