M58 Ballast problem

I could be wrong here, but I don't think coils as in your ballast go bad by the voltage going low unless it was shorted out and it would not last long if that was the case.
I read the few post on a website devoted to over driving Metal halide lights.  in order to ver drive them you change the cap for a larger one.
it did not take much of a larger cap to up the voltage.   I would check if the new cap has a higher value than your old one
http://www.lumenlab.com/forums/index.php?showtopic=10907
over driving sounds like a bad idea with a reef tank as who knows what the output is and how long it will last.

 

Joel, do you want to swap for the two-month-old dual ballast I'm no longer using? I feel like an *** simply for having sold that to you.