Wellness and struvite stones?

I've seen on the internet that some people have noticed a higher incidence of people feeding their cat Wellness, especially Wellness Core, and struvite stones than with other brands of cat food. I have in the past and currently feed my cat Wellness canned, their grain-free selections. My kitty did have a struvite stone in the spring, but it was probably more linked to dry food than anything else.

Last week, however, she was eating 1/2 Wellness and 1/2 raw Nature's Variety, and the vet said her urine was 7. No crystals, stones, or bacteria. The urine was drawn in the late morning, about 3.5 hours after eating. Normally she has urine drawn during the late afternoon and the previous 3-4 reports since the stone incident all measured 6.5.

So I'm wondering if I should switch her off Wellness? My ultimate goal is to get her on 100% raw, but I want to correct the pH level first and need a known safe measure I can retreat to in case raw doesn't work. Wellness does advertise a target pH of 6.1-6.5, and she did have those other tests that were 6.5, but the frequency of people mentioning feeding Wellness and struvite stones bothers me.

This is worrisome as my kitties main diet is grain-free Wellness (incl. Core). They also eat Blue Wilderness, Evo, Innova, and Weruva. Merricks is only occasionally tolerated.

jlc20m

We have a 10 month old female foster kitty and we've been feeding them Wellness regular dry and Wellness canned. She is now on antibiotics for a urinary infection and there are crystals present as well as blood in the urine.  I have to take her off the Wellness and go to a prescription diet.  This is the first time I've had an issue with Wellness products, but I have to admit that I've used Wellness mixed with other dry foods, such as Wysong Geriatric and Max Cat.  This is the first cat we've had with urinary issues. 

Tim developed crystals in his urine after we switched the cats from 90% free-feed dry to 90% Wellness grain-free canned. The crystals did not form a block; this was picked up in a routine urinalysis (he'd had enough previous urinalyses, which is why I knew the crystals were new). We took him off the Wellness varieties that contained fish (turkey & salmon and chicken & herring), and another urinalysis 10 days later showed no crystals, but a urine pH of 7.0. Because he had so many other problems and I began to suspect carageenan and/or chicken, we stopped Wellness altogether. His last urinalysis a couple of months later showed no crystals and normal pH.