Has anyone tried any other litter in their cat genie?

I was thinking feline pine or something flushable like that. I have the cat genie side shields and hood and my cats still kick the litter all over the place. Also the cat genie itself flushes a whole bunch of litter each time because it doesn't sift the litter enough to just get the waste. Just trying to save money its so pricey for 3.5lb box of granules.