Help with lighting

[Todd]

Hey Guys,

I picked up a new actinic bulb last night as I have been running regular fluorescent bulbs since I upgraded tanks (in addition to the MH). However it doesn't want to fire for me. As far as I understand my ballast should be able to run one of these bulbs. The ballast is wired for to run two bulbs right now, but I only put the new one in and took the others out.

This is the ballast: WH7-120-L Workhorse 7 Electronic Ballast

and this is the bulb: Coralife VHO Actinic (T12)

Does my ballast not work for this bulb, or is it the way it is wired? Any help?