Okay! So! I've done some research - my head is about to explode (again).
Luckily DH is a scientist, so I had a few
moments and he was able to help me a bit. I feel like I need a PhD in chemistry to understand all this - and I barely passed chem in high school.
The doctor I like at their current vet (who is supposed to be their nutrition person) called and talked to me for a while today. I asked her to please explain why Hills c/d and Royal Canin SO work - unless they have magic fairy dust, there has to be a reason why they lower the pH of the urine and prevent the formation of struvite crystals. She said that Hills has potassium citrate, that's one of the things about it that's special that lowers pH in urine. But the kitties don't like it and won't eat it and I don't really care for the ingredients, so that one is out. She also said that she believes that what we've done thus far, eliminating dry food altogether and going all canned and
adding water to their canned food will make a huge difference. BUT - since both cats appear to have a high pH and struvite crystals, it may be that this isn't a good choice of canned food for them, they may need something with less phosphorous.
So I went here
and DH and I looked at the analyses for all of the foods we're considering, as well as their current food. It looks like their current canned food is high in phosphorous - twice as high as it should be. I looked through all the previous threads on this subject as well as sugarcatmom's suggestions and we looked at Wellness CORE turkey/duck and Merrick Cowboy Cookout. Both look like good options - both have almost half
as much phosphorous as their current canned food, half the amount of carbs as their current food (and 1/5 the amount of carbs as the Rx option, go figure
), and are low in magnesium. I'm going to call both companies and ask them the target urine pH range for their products.
The vet told me I could call her on Monday and share all of the info I've found with her, and she'd take a look at the products for me.
So I have a plan of action:
1. continue their all-canned water-added diet
2. call the companies on Monday morning (Wellness and Merrick) and ask about the target urine pH of the 2 products I'm interested in
3. call the vet and tell her what I've found
4. try to phase-in one of the new canned foods
5. re-test urine with an in-house test at the vet's office (to prevent the formation of struvite crystals in the urine in the time between when the urine is obtained via cystocentisis and when it's tested) in 2-3 weeks
I think this post was more about putting my thoughts down on "paper" than anything else - so I apologize if I'm babbling a bit.
But I feel a lot better about the whole situation. Thank you everyone for your help. Of course chime in anyone if you have more input - and I'll keep everyone updated.
ETA: Daisy and Fitzy say "thank you" to you all for your help.