Our UV lights are mostly based on fluorescent bulbs. These bulbs require a special ballast to operate. Lots of folks buy surplus transilluminators on Ebay and upgrade them to very powerful SW lights using off-the-shelf bulbs and new electronic ballasts. When asked, I always recommend Fulham ballasts. They have a complete line of ballasts which will drive anything from a 9 watt bulb to 240 watts.
So if you're upgrading a "trannie" (DIY instructions here) or simply building your own light, use this chart to select your Fulham ballast. (Of course there are other manufacturers, but I've tested Fulham - they just work).
Fulham Ballast Selection Guide