Back in Oz when I had 2 Rotties, the poorman's solution worked for me.

Yellow spots on the lawn are caused because your dog's digestive system is too rich in nitrogen therefore the high levels of nitrogen in the causes the lawn spots. That is because the nitrogen that burned the grass is too strong but the outer edges of the 'circle' of ended up with just enough nitrogen to help instead of hurt.

There are a few things you can do. If you are observant you can water over the spot where the dog has ed this will dilute the nitrogen and will be beneficial to the lawn. Set aside an area the dog can use as a bathroom where you don't care what happens. Fill it with shingle or just leave the grass there to get burned. Teach the dog to go in that one spot. This will take time and patience.

Alternatively a dose of one teaspoon to one tablespoon of apple cider vinegar (depending on the size of the dog - mine were large pets) per day can correct the pH imbalance and could solve the problem.

The apple cider vinegar can be added to the dog's water or put directly on his / her food.

I have also tried this method which works with my pets. Take two tablespoons of tomato juice on the dog's food twice a day and it will have the same results.

The shelf product I used was Dog Rocks.

Sorry can't help you further over here ( got no pets here in CH at the moment ). This site might help.