Becky, you could also look at the Royal Canin prescription foods. When Ariel had her stones we looked at both Science Diet (Hills) and Royal Canin and choose to go with Royal Canin because the ingredient are a bit better. Not great, but better than Science Diet. Of course our vet had to special order the food since the office carried Science Diet. However my vet actually uses Royal Canin prescription over Science Diet for her cats as well. Our new vet (after moving across the state) carries Royal Canin prescription and Innova in her office.