One does not need a UV light to stimulate them; they do that on their own. The key is partially location but mostly the right time, which starts about 45 minutes after sunset, and continues for an hour at most, on certain days only. Those days are a day or two after the full moon for about 10 days or so. The point is it has to be dark, really dark, and your eyes need to be dark-adapted. To be dark, there can be no moon during the observing period. Tell me which days you were looking for them and I'll tell you (from sunset and moon tables) if those were good nights or not. Locations? Pretty much anywhere there is coral, from about 2-30 ft down to at least 50-60 feet. We've seen them in front of Buddy Dive and Sand Dollar, but they were spectacular at Petries' Pillar on a night boat dive. the Lake is another popular viewing spot; just about anywhere it is easy to do a really dark entry and exit.
Mel Briscoe, Alexandria, Virginia