Jen!! We just had the same problem with Sam!!! I was able to look at his urine under the microscope at the vet's. He had a crystal that would have made any bride proud to wear as a ring on her finger!!!! Sam is eating SO canned with 40cc's of water blended in at each meal. He is also getting Dasquin(sp)and Elavil. The Dasquin helps the muscles of the bladder, and the Elavil is to help with the same plus helps keeps the stress down!!! Good luck with Sterling.