or call them at 1-800-826-7206. They have a few products you can use on existing brown spots. They also have a couple different "treats" you can give your dog that acts as a neutralizer against the ammonia in the dogs urine. I've given these to my lab/rott and it worked real well. The product I bought, and would recommend, is "Lawn Guard Treats". Give them (quantity of treats based on dog's size) as a treat in the morning. I didn't notice any change until after a few days of giving him the treats.
Brown spots (groan). I hear ya. I used to have two golden retrievers that did their damage. I found two things helped. First, I changed their diet at the recommendation of the vet. I put them on a low-calore feed (Eukanuba large breed diet). That helped like you wouldn't believe. The acid in their urine is killing your lawn. The only other thing that I can think of to try is to suppliment their diet. Talk to your vet, they can help. I have no more brown spots!