I went to a lighting store and they didn't have them. doubt hd would have it.
I'd be interested in replacing the ballast with another brand if it's 3/5 on a difficulty scale, I'd be willing to try it, but since it is electricity, I'm a little wary. And there are so many bulb & configurations I wouldn't know where to start. Not to mention it's part of a mh/pc/moonlight light unit. ??? dunno.