I use Tidy Cats clumping litter. And I also swear by the Arm & Hammer powder stuff, it's the BEST!! I have hooded boxes but I also have a plug in air freshner right behind Taz's box that I can control the level on. I don't have one near Paizly's since her's is in her room and not out in the main area of the house. But I do have one for when she moves out into the world someday.
I can tell when the oil gets low in the plug in because you can start to smell the box.