There is some controversy regarding whether UV light increases THC. I have a couple of t-5 "lizard lights" in my tent.
I used them for a few grows, then DIDN'T use them for a grow, and it seemed the grows that got UV were a little more potent. But the reality is there could have been some issue with the grow that caused it to be not as potent, I was basing the difference on memory, rather than a side-by-side comparison, and it was only a single instance.
I've never heard of anyone using "black lights." I would go with something made for exposing living things to UVA and UVB light, like lights for cannabis or lights for lizards.