Find out which light sources are recommended for each growth stage of your plant.
At germination (and for clones):
Fluorescent light will be all you need. You can use Metal Halide (MH) or High Pressure Sodium (HPS) lights as well, but you don't need this level of intensity, and you definitely don't want to burn your young seedlings, which can be more likely with a hot High Intensity Discharge lamp such as the MH or HPS lamps.
For Seedlings & the Vegetative growth stage:
Metal Halide lights are recommended due to their enhanced blue spectrum which encourages bushier, more compact growth. Once your plant has reached its vegetative stage, you really don't want to use flouro's if you can help it, because they simply aren't as effective. A High Pressure Sodium light is certainly acceptable for this stage.
For the Flowering growth stage:
High Pressure Sodium lights are the best suited for flowering, and if you are only going to be using one light for the entire process, the HPS will be your best choice.
Subjective commentary:
Durotest Aquatinic 7500K bulbs are an excellent choice for cloning, seedling and mother plant lighting, for which they keep growth sturdy and compact. Switch to SunMaster Cool Deluxe metal halide during the early vegetative stage through the stretching phase of early flowering to keep the plant compact. Then finish off the plant's flowering cycle with Hortilux high pressure sodium lighting. They are extremely bright and efficient with superior dispersion.
