I don't think that's your source
First, I doubt if they're urine crystals...anything that hard to remove has to be sea water minerals, and minerals don't stink, especially after that much scrubbing. But I'll bet you have another problem you don't even know about...'cuz if there's mineral buildup in the bowl, there's also a lot more mineral buildup in the head discharge hose and even on the joker valve. If that's the case, the source of your odor may be the inside of the head discharge hose--not from the minerals, but from waste in it that's escaping into the head through a joker valve that can no longer close. So you need to discconnect the head discharge hose and inspect both the joker valve and in the inside of the hose. If there's buildup, it must be removed before it reduces the diameter of your hose enough to create a clog or so much backpressure that the toilet becomes hard to flush. Mineral buildup be dissolved with muriatic acid...and prevented by just putting a quart or two of clean fresh water down the toilet at the end of eveny weekend.
