When we were at our max (5 cats) we had been using Tidy Cat multi cat...when we dropped down to 3 we figured we would just stay with that but it seemed like they changed it. "cause all of a sudden it was more dusty and didn't do as good a job or last as long. We've been using Johnny Cat and it works wonderfully. The only time there is any smell is right after someone is in there but it goes away real fast...which is a good thing considering there are 4 litter boxes in the house