The first thing that comes to mind is to create a 'pee place' for her and train her to use only that spot (lots of dog owners do that.) The other thing you can do is to immediately pour a half-gallon or more of plain water on the pee spot when shes done to dilute the urine. The lawn actually likes the chemicals in the urineit just cant tolerate it concentrated in one small spot. I cant vouch for the products that you feed your dogchanging the chemistry of her urine means that its also changed inside her bladder. Id ask your vet about that before trying anything.