Any blacklight will do. Make sure to get a cleaner that has enzymes in it. (Like Nature's Miracle) You want enzymes to break down the pee, not just some perfumed cleaner to mask it (kitty can still smell the pee if it is just covered by a perfumey smell).
Male cat? They are more prone to crystals in their urine. You may want to take him to a vet. Ours had crystals and we put him on special cat food and that seemed to (mostly) fix the problem. The crystal make it hurt when they pee, so they start to associate their box with the pain and start going elsewhere.
Also - make sure his box is always clean. I have read offering multiple boxes sometimes helps (some cats like to pee in one and poo in the other).
And sometimes it can be behavioral due to: New baby, new people in the house, not petting/playing with him as much, new pets, etc.
Lol - sorry to write a novel. I used to work at PETCO and have done a lot of reading on the subject. Now, I am trying the final option: finding my kitty a new, loving home.
"I'd rather waltz than just walk through the forrest"
- Sprint Triathlon: 9/11/2011
- Half Marathon: 9/18/2011
- Weigh under 210: GOAL!!! As of 7/16/2010
- Next goal: Get BACK to under 210