Tomato juice!! Someone told me to add tomato juice to the dogs food
daily and the acid in the juice would dilute the acid in the dog
urine. At first I thought they were crazy but it did work, the
following spring I started giving both dogs tomato juice daily and no
brown spots. I've been spot free for two years.

I hope this helps, it's also a lot cheaper than the other stuff you
buy.

Heather