Which Prescription food is best for preventing crystals in urine?

My 6 year old cat Ella has now developed crystals in her urine. I have had her for 3 years and as long as I have had her she has not had this problem before. The entire time I've had her she has eaten Wellness Core both dry and canned. She is a good water drinker I would say. I have tried a water fountain within the first year of getting her because my one male cat (Ella didn't know him) had kidney disease and loved drinking out of the water faucet so I bought a fountain and he loved it. Well, Ella hated this and it wasn't like it was loud or anything! She just plain hated it.

Anyway to make a long story short, the vet has her on a prescription diet right now which is Science Diet C/D. I am glad I looked at the ingredients closely because there are biproducts in there and perhaps a few other things that are not found in Wellness products.

I was just looking at other urinary prescription items online and they are the same. I have to say I am disgusted because if veterinarians help to come up with these they should know what is healthy for our animals?!?? What are THEY feeding THEIR animals when they have these problems?

What are your thoughts? Am I being overdramatic?

Here's a good web site to learn more about diet and urinary problems: http://catinfo.org/?link=urinarytracthealth

And this for one vet's opinion of prescription foods: http://www.catinfo.org/#Prescription/Therapeutic_Diets_

I've heard that Wellness can cause urinary problems in some cats. Maybe you can stop the prescription food and try feeding a different brand of commercial food? Canned food is best since getting lots of water into the body will help keep the urine diluted.

I also have a cat with urinary crystals (he's blocked twice and had cystitis twice since then). I agree that it's frustrating that these foods aren't the best quality, but in the end, what matters, to me, is that it works. The website LTS3 suggested is fantastic. It really emphasizes an all wet diet as key. I've switched my Rocky over to wet c/d food that I supplement with higher quality wet food. I look at the percent composition on the back & see if it matches or beats the hills c/d. He previously only ate dry c/d. There are lots of other threads on this subject that could help you. Just do a forum search. Hope your kitty feels better!