My light is getting dim so I decided to look for a new bulb and found this site http://www.prolighting.com/bulbs-hid...re-sodium.html. What I notice is these very cheep bulbs have the identical specs as many "grow bulbs". Is the word "grow" on the packaging the only differences? This bulb will be for flowering only so should I pay $30+ for a "grow bulb" or get three of these?