good idea, but the math doesn't work ... while ten 50-watt CFLs total 500 watts, and perhaps as many lumens, etc., as a high-pressure lamp, they don't 'penetrate' the canopy ... fluorescent lamps' lumens fall off very quickly, as distance grows ... you might have 25,000 lumens 'up close' to the canopy, but, it may be 1/2 of that, just inches away ... you would be MUCH better off to buy a 400w, or 600w HPS (high-pressure sodium) lamp, and fan-cooled hood ... HPS works just fine for vegetation phase, too, if you can't afford a switchable ballast ... IF I was to go back to fluorescents (I used them for many years), I would run the 40w tubes, not CFLs ... they run much cooler, allows even light distribution (line your plants up under it, shortest, to tallest) ... I was up to 16 40-watters :wtf:, when I got my first 400-watt HPS ... it blew the fluoros out of the water, no comparison ... hope that helps :jointsmile: