Okay. The C/D and S/D are both for struvite crystals. They are far easier to treat than oxalate so you are in luck. They also happen to be the same crystals that my Sydney has/had. Struvite crystals usually form when the pH is too high. Once the pH is lowered, the reaction that causes the struvite crystals to form can no longer take place. However, caution is needed not to take the pH too low as oxalate crystals will form if the pH gets too low. A slightly acidic pH, around 6.5 is considered about normal.
My vet suggests that Syd's pH stay somewhere between 6.0-6.5, no higher. We have started testing her urine with pH strips to alert us of any changes. I bought the pH strips from my vet but you may be able to get them at a drugstore. Basically, just place under the urine stream (after giving the cat a bit of a head-start, you do not want the beginning of the elimination) and then compare to the chart given with the strips.
Now, the food is formulated to bring the pH down (check for methionine to be high on the ingredient list). There is another product, called Methigel, that is a methionine supplement and is a urine acidifier. However, you are not supposed to use the Methigel with the food (the food probably has a warning about using additional urine acidifiers). Wysong makes a product called Biotic pH- that is supposed to lower pH and Solid Gold makes another product called Berry Balance (that we are trying) that does the same thing. I would consider that supplementing with these products would be a last resort if he still won't eat any of the other foods that I'm about to mention.
There are many other prescription foods out there for the dissolution of struvite crystals. Waltham's, Eukanuba, and IVD, are a few. Your vet should have access to all of those brands...and possibly more. I would try one of those foods if he isn't eating. Not eating can cause a host of other problems, including fatty liver, that you do not want to be dealing with right now.
The probiotic needs to be administered at least 3 hours after the antibiotic. Otherwise, the antibiotics will kill the probiotic and defeat the purpose. I give our cats powder acidophilus by Webber Naturals
. It doesn't contain dairy and have a high bacteria count.
Once he is eating the wet food, increasing his water consumption should be easier. I add about 1/4 cup to Sy'd wet food at night and she usually drinks it all. Remember, their full bladder is only about the size of an unshelled walnut so every little bit counts. We bought a Drinkwell Pet Fountain for Syd and she drinks considerably more. Here
is the link if you are interested. They are more expensive than the Pet Mate one but I feel that most cats prefer this one because it is a real stream of water...much like the faucet.
Finally, about the bladder palpatation, you should be able to feel if he is having troubles again. The bladder should be soft and squishy and fairly small, like I mentioned. If it feels hard or larger than a walnut, you should probably contact the vet, ASAP.
I think I have managed to spill my brains but there are probably some things that I have missed...