Carrie- From what I have read about struvite crystals in dogs and cats they can be managed WITHOUT a rX diet. You can however for a short time feed the s/d and then just like C4C said, PLEASE talk to a holistic vet (they often do free phone conslutations) about a better diet for your dog.
I do not think that rX diets are worth the money and I think (and others do too) that they are another marketing tool to force you to spend your money with them for the rest of your life. I was told when my cat had a UTI that he had to stay on Royal Canin Urinary SO for the rest of his life. I wish I had known what I know now about just keeping him on a species appropriate canned diet.
