FLEAS....gross

Hello all! I need some advice/personal experience. My husband & I moved to a different apartment in January, and almost immediately my boys got fleas. Our apartment is right next to a large wooded area (like 15 feet from our door), and there are literally dozens of stray cats who live in the woods & our parking lot. We never once had a problem with fleas in the 2 years we were at our old apartment, so I'm thinking that it's bad because of all of the cats around here.

My question is have you found a flea treatment that works for you? We have tried frequent flea baths, flea collars, flea drops applied to their skin, etc. None of them have worked. Are we going to have to get something like Canine Advantix from our vet's office, or were you successful with any other store-bought treatments? We haven't tried flea bombing the apartment, but if that worked for you, please let me know, too. Thanks!