GrassSaver Wafers, 300 Count (1017163)
The ingredients in GrassSaver Wafers, 300 Count lower the pH of your dog's urine so it doesn't turn grass yellow. GrassSaver is a nutritional supplement that is good for your pets, comes in a variety of palatable forms, and keeps your grass looking great.
I don't know if this works yet or not because I just placed my order. The price here is better than anywhere else I looked, though, so I thought I'd give everyone a heads up.