Royal Canin - Control Formula kibble from the vet is what we've been feeding our cat since he had a major crystal problem a year ago. He and his two friends love it and there have been no more bladder problems. If your vet has your cat on an Iams food, it may have similar ingredients.

Plenty of fresh water is always available which they prefer in the shiny stainless steel dish, or from the automatic drinker (which is on the fritz at the moment).

Some additional information is needed.

What species is Seymour- dog or cat?
How old is he (phosphorus can be increased normally in young animals)?
What type of crystals?
How many crystals?
Any clinical signs such as straining to urinate, blood in urine?

I always recommend canned food for cats. In dogs it depends on the crystals.

people are finding great success with a tiny drop of liquid chlorophyll in the drinking water, swear they have saved their cats with it. Tiny drop, though, or the cat will never drink it. I don't know much about it, but you could read up on it.