I don't have an answer I'm afraid. The stray cat Panther I took in many years ago would not use a litter tray but would use the bath. I even put the litter tray in the bath. All I can say was that it was easy to clean.

I did find that my cats wouldn't use a litter tray if I added a scented liner or added spray/power to de-odourise and there were certain cat litters they didn't like. Funny little beggers aren't they.

Sue