Mobile Bay Reef Keepers

I have a ballast I need to wire up but there is three wires. One is a grounding wire, what exactly do I hook this wire to?...I know I am an idiot.

If your are talking about the wire to the wall, it goes to the grounding prong. If you are talking about the wire to the reflector/penant, it goes to a connection on the reflector/pendant. Most times if the reflector is already wired with a mogul base, there is already a wire connected to the reflector for your use. If there isn't you need to make a connection.