Currently using a 400W sodium light in an outdoor floodlight fixture. I'm not sure how many watts it actually uses; probably close to 500W and although the bulb is very efficient the fixture is not. So I'm thinking about one of these (haven't decided which of the 2 yet):
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4-lamp version)
What do you think? The fixture from FullSpectrum has a more efficient ballast, but the energy payback would take a long time. Also I wonder if the included 5900K lamps produce enough red spectrum for efficient use as a grow light. Of course I could pull 1 or 2 of the lamps out and keep them as spares and replace with 2700K or 3000K tubes.
Bob