Huge Urinating problem - Help

It sounds to me like a stress issue. If all urinalysis tests have been normal (and I would suggest doing another if you have only done one) it doesn't mean that the bladder is normal. There could be inflammation of the bladder wall due to stress. When cats gets anxious or stressed it goes directly to the bladder and the cells of the bladder wall multiply and open up to allow urine into this area where no urine should be and then you have irritation and then the cat has the urge to urinate to frequently. I have a cat with stress related bladder problems and that is how the Specialist explained it to me in Laymen's terms. All cats are different and what causes one cat stress in the same household might not even bother the other cat at all.

I use a product called NOK Out ( ordered online only) or Stinkfree ( sold at Petsmart). Blot up all urine first, then douse with product and blot again, then douse some more and leave it sit. It could take up to two days to completely dry, but it really works. I would also suggest buying Feliway plug-ins, sold at Petstores. These have the natural pheromones of cats and are very calming. Do you have tall vertical cat trees so the cat has some place to get up off the ground and play/rest? Do you have interactive wand toy sessions with your cats? This will help burn off some energy and help Scar to relax and feel satisfied. Do you keep the same schedule each day for feeding, cleaning cat pans, playtime etc? Cats needs a routine to feel secure, they like to know what to expect each day. Do you have at least two large open litter boxes? Dr. elsey's Cat Attract litter would be good to try at this time too.
You can also place upside down plastic carpet runners in the spot where Scar is going to keep him away. Or place a food dish in that spot.

I think I would run another urinalysis, or a culture sensitivity Test on the urine. This problem can be solved and usually it is a medical problem over a behavioral one. I really hope you can get to the bottom of this. It sounds like Scar has been moved a lot in the last two years and might just feel insecure at times which causes stress which can lead to bladder troubles.

I know it might sound a little wierd but I use tough suff carpet cleaner. You can find it in the automotive are at WalMart. It takes out the smell and the cats and dogs I had never went to that spot again. It has many uses. It cleans fabric, carpet and vinyl.
Hope this helps.