I find that I need to put more then 3 inches in the box or it sticks to the bottom. I have used MANY different types of litter, and I find this to be the best overall. It has its small issues, but it is the BEST at odor control and I know it is natural so that makes me look past the little sticking issue. The big clumps tend not to stick together well, but I just need to sift more to get the little ones.
I'm lucky, my cat will use any litter I try and switched him several times before I found Swheat Scoop.