The light is a 24" Giesemann, so it only has one MH bulb with four T5 bulbs.
I've looked for instructions online but haven't found anything yet. I was wondering if the extra power line could be for electronic control, as the one instruction manual I found (which had no illustrations) mentioned that.
I'll give Wendal a call at OA and ask him, he sold it to me
Thanks for all your help guys, I appreciate it.