Odyssea Light fixture problems

[asylumdown]

I have a 750W Odyssea metal halide light fixture. 2X 250W metal halide bulbs, 250W actinic T5s.

I know it's pretty cheap fixture, but it's worked great for the past year. Tonight I replaced the 15 000K stock MH bulbs that came with it (it's been a year) with 10 000K 250W coralife bulbs. In the process, I broke one of the original bulbs.

The problem is that neither of the new bulbs will ignite. When I swap out the not broken original bulb, it ignites no problem, but nothing I do will make the new bulbs, which should be identical except for colour temp and manufacturer, ignite.

At this point, my tank has no lighting and I'm kind of freaking out. Is there something obvious that I'm missing? They're double ended bulbs for a double ended fixture, shouldn't they just ignite?