Is this what youre talking about: http://newandusedgrowlights.com/shop/hoodsreflectors/neptune-6-cool-tube-reflector/
And will these bulbs be sufficient: http://www.amazon.com/iPower-GLBULBH600-600-Watt-Magnetic-Digital/dp/B005HJJ7TY/ref=sr_1_1?ie=UTF8&qid=1399661927&sr=8-1&keywords=HPS Bulb...
Yea, HPS/MH bulbs are quite cheap ($10ish) but its the reflector and ballast that are quite expensive.
But i am able to get 4-6 42Watt CFL bulbs (2700k and 6400k) so i think this path is better, especially since i can use both the 2700k and 6400k at the same time (say 5 6400k and 3 2700k for...