Urine stains

Question
HELP!!  I have a red roan appaloosa who is 99% white.  She has a permanent urine stain on her left hip/gaskin area. (She lays in the same wet spot in her stall every day)  I am out of options.  I have cleaned her stall twice daily, cleaned the stain with Quick silver everyday, I've tried spraying it with hair polish everyday, left conditioners in it, applied oil to keep the stain from sticking to it, tried feeding her oil, keeping her blanketed,  UGHH!!  I show a color class so hiding it with powders or whiteners is not an option.  I've heard of laundry bluing but don't know how to apply it or if it will remove the stain or just make the white on her whiter.  Any suggestions will be appreciated!!  
Thank you!!

Answer
Horses don't lay in urine in the wild.  You lock the horse up, the horse has not place to lay that is clean and urine free, so it has to smell her own urine what is bad for her respiratory system, the urine is acidic and probably burns the horse's skin, and your question is how remove the stain so YOU can show the horse.

Here's a thought, take the horse out more, clean the stall more, let the horse spend more time out of the stall, lay down more bedding (straw or chips) or how about you spending just one night in the stall with the horse and see how bad it is and see if like wearing a blanket soaked in urine.

Good luck at your show you may not win for her color but I am sure you wont win for your horsemanship skills either.