Need help with wiring ballast and air cooled hood

Fellow growers,

I know nothing about wiring ballasts so I just need to make sure i can go on with this before i burn the house down.
I was using a 250w HPS before and I have now upgraded to a 600w ballast while using the same air cooled hood. So I just disconnected the 250w ballast (which a friend hooked up for me) and connected the 600w the same way.

The bulb did fire up normally. I turned it off after couple minutes and noticed the bottom of the bulb was black. I just borrowed that 600w HPS to test my new set up and honestly I'm not sure if it was already black before I used it.

Can someone please check if I did it correctly? Is it normal for the bulb to turn black?

Thanks!

My bulbs turn a differnt color on the bottoms than the top. i would say if it turned on, it is wired correctly.

i hope so.. thanks for answering!