Cat urine fluoresces fine when using the right light. The only bulbs I’ve seen that work correctly for your use are the bar-shaped ones. I’ve used the LED kind and don’t find they work as well. You also have to be fairly close to the stain for best detection, say a foot. In this link, I have used the 10.5" one and it worked fine, turns out old vomit stains fluoresce as well, but not as brightly as urine.