'Royal Canin Urinary SO' is for the same problem but it's not much better ingredient wise.
I went through this recently with my male cat, his urinary tract was completely blocked before he showed me any symptoms, so he need surgery. the vet put him on s/d then wanted to switch to c/d. I used the s/d for 1 month then took the risk of switching him back to his regular food, but I added canned food (and now some raw) to his diet to balance out his pH levels and keep him more "flushed" out through extra hydration. It's been 5 months and no reoccurance. I had a urinalisys done by the vet last month and no bacteria, pH levels in the right range
.
I'm not too familiar with it in dogs but I do know that the c/d is a bit lower in protien and minerals which helps maintain the necessary "acidic" urine.
If it was my dog (this is JUST what I would do, don't take my word as gold here, I'm definatly not a vet) I would go with a food a little lower in protien (like 18-20%) and add wet food to make up about 1/3 to 1/2 the daily diet. I would then get a urinalysis done periodically to make sure everything was in the right range and no more crystals were forming. If they came back, I'd use the RC SO or c/d.
I know the ingredients aren't great in prescription foods, but depending on how severe the problem is, sometimes you have to use them long term. You do need to work closely with your vet though, if the one you're with won't consider even trying an alternative, you can seek a second opinion or talk to a veterinary nutritionist about an apropriate yet healthy diet.