I have found products that color or paint the grass. Products to spray on the grass that help it recover from the nitrogen effects of the dog urine. I have found products to feed your dog that supposedly change the PH of the dogs urine to less acidic. There are all types of products to feed your dog to fix this problem of dead grass spots in your lawn. Wafers, Biscuits, pills, liquids that you add to the dogs drinking water and more. I have also found grass seed designed for reseeding those area's in your lawn. All of these may have their place and do the job. I do not know I have not tried them all. Different solutions work for different people and their own situations. I will tell you what I have been looking for. I am looking for a product that you sprinkle on the lawn (similar to weed and feed) in the areas that the dog urine is killing. This product will then bind the nitrogen and change it so it becomes fertilizer to the lawn and not so concentrated that it burns it. I thought I had found just that product but I could not get the company to respond to my inquiries. I am looking at another lead on this kind of product and I will let you know when I find it.
I don't believe the PH has much to do with urine killing the grass. I think it is the nitrogen content in the soil from the urine that kills the grass. Especially if you have treated it with a lawn fertilizer that has nitrogen in it already. I have read several reports about it. I have not done my own study on this but the nitrogen makes more sense to me.
There are natural ways to deal with the problem that don't involve buying anything extra. Watching the dog and each time it urinates on the lawn you can dilute it by adding water to the spot. Three times the amount of water to the amount of urine within eight hours of the urine being deposited is recommended to get resutls. Personally I can't or won't do this one. I don't mind diluting it when I see the dog urinate in the yard but I am not going to watch every time for it. You can change the dogs diet to one that produces less protein waste. This will reduce the nitrogen in the urine. Either a lower protein diet or a food that the dog digests the protein better. Check with your vetrinarian. You can walk the dog regularly so it urinates in a place of your choosing. If it is a neighbors dog causing the problem advise them of the leash laws. Then there is the option of potty training the dog to use a specific area of your yard. An area you have designated for your dog to go. Get your dog to drink more. You can add a little water to your dogs food. This will dilute the nitrogen in the urine. Your dog may need to urinate more often but it will be less damaging. These are all possibilities where you do not have to buy anything more than you are already buying.