The site again is a good informative site showing your what's involved as well as part numbers......If you contact Graybar they should be able to hook you up with the ballast and parts you would need to drive a 175 or 250W MH......You can also get the exact same parts from Hellolights, but not sure on price.......I would beg to disagree with his info as far as the best bulb, because that again depends on what's driving the bulbs as far as what PAR readings you'll get......Iwaski bulbs can only be driven with certain ballasts as well, or I should say to their full potential on the correct ballast