what to use for fleas?

Talk to your vet and see if you can get Capstar - that is an oral medication that will kill all live fleas in 24 hours. Then the hard work - shampoo the rugs - bomb the house - get under the couches, wash all blankets. Choose whichever product you think works best - frontline, revolution, vectra, advantix... and stick with it for at least 6 months. The problem is the eggs - they can hatch anytime, so it may seem like you got rid of them, and then suddenly you'll have a problem again.

I have mine on Trifexis right now and that treats not only fleas but worms as well.

Also, you may think that these are not working but the fact is that with a lot of these medicines the flea has to first bite the dog before the flea dies...which means you still may see fleas on them every now and then. Also, what i have done it the past is spray the yard for fleas, then spray the house for fleas and then give your dogs a bath in some sort of flea shampoo or Dawn and then apply/give the flea meds.

Comfortis,Revolution or K-9 Advantix II would be what I try next,Frontline is known for not working recently.Good luck and I hope you can find something that works:)

Yikes,you must have stubborn fleas.You didn't say anything about K-9 Advantix so I would give it a shot and see if it works,if not,consulting with your dog's vet might be the next option,as he/she may have recommendations for something that works.