Last weekend, Ivo had a little accident on the carpet (I had to take her to the vet's, and she got so scared she peed on the floor when I picked her up). I treated the spots with a urine remover my vet recommended and borrowed a black light from work to ensure I got all the spots.

My question is this-some of the urine spots are still fluorescing under the black light, though I've treated them four times. Should I expect to see some glow, or should the treatment get rid of all the glowing spots? Ivo has not seemed interested in the spots since they've been treated.

Depending on what your cleaning with, what you're seeing could be the cleaner and not the pee anymore. Try putting a little on a spot that shows nothing under black light and then check to see if its the cleaner. I worked somewhere that has all black lights for two years-- you'd be amazed at what shows up!

Did you use the urine solution enough to soak into the backing/underlay of the carpet? I hadn't done this so well on Molly's accident spots and I could still see the glow!

You should also let it dry naturally, which could take 24-48 hours.

After a generous treatment, the glowing disappeared. :)