copy and paste the following it explains exactly what struvite urinary crystals are....and like I said this is very common in male cats and commonly the reason they pee outside the litter box.....but DO NOT use the dry food that is recommended on that page, what you need to do is feed a canned wet food to your kitty.....this problem is caused by a state of dehydration and feeding any source of dry food will only make the problem worse. get some canned food and be sure kitty has lots of water nearby always.
http://www.marvistavet.com/html/feline_struvite_bladder_stones.html
I do not think the Vet has done that type of test. I will suggest looking into that route as soon as my father gets off of work. Thanks!
has the Vet done a C&S for a UTI or Crystal in the urine? this is very common with male cats especially...its very painful when they pass urine, like us when we have cystitis..than they associate the pain with use of the litter box and pee elsewhere looking for relief.
I'm surprised all the other cats aren't using the same areas now b/c they too can smell the urine, cats go entirely by scent, if they can smell urine they presume its the spot to use...
i will give you a site with some info, however I don't put much hope in the homemade urine erase that they give...but does give some good medical tips.
http://www.catsofaustralia.com/kitty-litter-box-problems.htm
I should also mention, that we have tried numerous types of litterboxes, got a 2nd litterbox and moved them into different areas, tried using numerous litter types and brands, and none of that has helped either.
The thing is, the cats are okay with sharing a litterbox, the male cat poops in it, the female cat does both in it, and the male cat will occasionally pee in it, but most of the time, 80% he pees on the floors.