You can also try Purina Layena Sunfresh (non medicated). I buy the 25 lb bags, as the one 50 lb bag I got had mold in it. So far so good. I use one 25 lb bag for 2 litter boxes and it lasts about 1 week for 4 cats. I have one cat who is very picky about having a clean litter box and the 1x per week cleaning seems to help. Definitely lighter weight than the clay litter. Makes it much easier to move/empty the box for cleaning.