Randi, I was also going to suggest that you have his thyroid checked out. You may also want another urinalysis done. My vet recommends that a cat with crystal problems should have one done at least every 6 months.

Storm turned 11 in Jan. and he had lost some weight due to a UTI. I took him to my new vet and had another urinalysis, bloodwork and thyroid check. His bloodwork showed that he had high calcium levels in his blood again so she did another blood test and luckily Storm's fine. He also eats the Royal Canin Urinary S/O dry and wet and loves it. He's now at 14.5lbs which is a good weight for him because he's a very large cat. I measure out his food and he only eats about 1/2 cup of dry at the most. He prefers to eat his wet food over the dry. Good luck. I hope that everything checks out fine with Fister.