Which sight would work better at a dimly lit shooting range?

I was using a Hi-Viz fiber optic sight, and the indoor range was rather dimly lit, and I probably could have used the white opaque light tube and had a better sight picture. And i'm going to try that next time also. I guess what I really want to know is if a tritium sight would work in a dimly lit, indoor firing range, or do tritium sights need even darker conditions? How dark does it have to be for a tritium sight to "light up"? I suppose there would be some type of measure of light, but other than measuring the light, I would like to hear opinions of personal experience from folks who have used both tritium and fiber optic sights at indoor gun ranges.