I just wanted to chime in and let you know that if you are buying it off the BAy from some guy named Elvis, out of NOrthern California (San Fran area) you should take heed. The price was right. However, the unit sucks! It was a 48" 2x 250 watt MH + 4 x55 PC, + moonlights.
He advertised the unit with new high quality HQI 20k bulbs which was BS. The two ballasts for the Halide bulbs were weak, tiny little silver ballast that are smaller than the ballast that runs my PCs. The fixture runs hot, i mean HOT! yeah for $350 bux it was okay. I had bad red slime algae growing after 3 months of having this to find out that the main cause of this is that the lights are bad, or have lost their spectrum. I spent 150 bucks on two new bulbs which helped tremendously. After 6 months of having the unit one of the ballasts just completely stopped working. I had to search all over the place to find a replacement because the wiring and quick connect he used is non existent in retail for fish tanks. It's the kind of plug you find on the back of a desktop computer. So, I spent another $200 on a dual ballast figuring the second ballast would burn out soon. So, by this point I am $700 dollars into this fixture. Looking at the similar hamilont units. I should have just gone for that. This guy has changed his name on ---- numerous times, and refused to respond when I asked him to cut me a deal on new bulbs. Since he advertised them as being new, and I only run the halides for 6 hours a day, and mine were shot after 3 months. If you are buying off of the BAy, don't buy this unit. It looks and sounds great in the picture and product description. Cheap bulbs, ballasts, and fans that dont move any hot air from the top of the unit!
Hope this helps. If i could do it again. I'd just have sprung for a nice light system. Oh well, i guess it's the story of the hobby!