I've heard many horror stories about carefresh infested with mites, clogging the noses of pinkies, and aggravating sinus problems. You must remember that these animals spend most of their time with their nose only inches away from their litter. It's best to stay away from kitty litter. The clay dust can aggravate myco symptoms. Yesterday's news or Cellsorb is a great alternative and pretty much dustfree. The only problem I had with it was it got soggy and smelly when soiled. I had to change it everyweek regardless.
I use Equine fresh now, (pelleted pine) most pellets are kiln dried, and dont have the oil's that will lead to respiratory problems.
I have tried a variety of stove pellets as well, and they were either very aromatic, or smelled worse when wet than the Cellsorb. I dont care for it. They absorb well enough.
There is also pelleted aspen available as another alternative. These pellets are in my experience the BEST choice for smell control. They are extremely absorbant, and will break down into a TON of sawdust by the time you need to change. Use only a little, because this stuff really does expand! Hope this helps ~C