I'm so sorry to hear that Pete is sick again.:( My Storm has also had the PU surgery and was on the Royal Canin Urinary S/O diet. I stupidly changed his diet to Innova and he got crystals again but luckily no bacteria infection. He's now back on the Royal Canin diet and is doing very well. All of my cats are now eating this and they love it. I feed them both wet and dry. This food prevents both struvite and calcium oxalate crystals and I also think that I read that the canned food helps cats with the idiopathic FLUTD. Here's the link to it Royal Canin Urinary S/O diet. I sure hope that Pete will feel better soon.