Each cat is individual, as every human is, so you can't apply the same rules to all the cats. Of course, it takes a while to realize what your cat likes and doesn't like. But once you figure it out, everything becomes easier. Regarding urinary problems, I had the same issue with mine, and this artic...

You can just add some specific amount of salt to avert many diseases of fish. It’s not necessary to use nitrates as germicidal in an aquarium. Using nitrates may harm the proper physiological functioning of your fish anyway. I can recommend you not to use them at all. When I had a similar problem,( ...