had a huge flea issue a couple years ago, fenced off a small area of the yard, and sprayed it down, covered the carpets and furniture with 20 mule team borax mixed with salt and dichotomous earth. Set off 3 times as many bug bombs as needed and left the house with the dogs. Took dogs to groomer had them shaved. It was a nightmare that went on for weeks until i did the above.
Would have been a lot easier to just switch them to a raw meat, organ, and bone diet. Fleas completely lose interest in your dogs. They like the sugar in the blood of dogs fed a commercial diet. Take that away, and the fleas will no more infest your dog than they would your coffee table.
