From what you're describing, he probably needs a prescription diet. Eukanuba sells one, and Science Diet sells one, I'm not sure who else. I know a neighbor with a poodle that has problem with bladder stones. If it isn't kept on the special food, it has so many problems! Get advice from your vet! Whiskas is an okay pet food, defianatly not a premium one, but I wouldn't recommend it for your cat. At the vet least go with a premium low residue pet food. There are some that are even designed for urinary track health-check the labels on some brands at your local petstore. Hopefully someone else will have better advice.