I have 2 cats and use Scoop Away Clean. They have a multi cat formula, but the regular formula works just as good. I get it at Wal-Mart. If they're out of Scoop away, I'll get Fresh step. I think they both work about the same, but Scoop Away is a little cheaper. Hope this helps!

P.S. I tried tidy cats but it did not work at all!! The "clumps" would crumble as soon as the scoop touched them. And it did nothing for the smell!!