I've never heard of a daily product. Had you contacted Merial in regards to the positive Ehrlichea test while using their product?
I have the same issues with trail running/hiking my dog. In addition to the Frontline, our vet suggested a collar called Preventic. It is only for adult dogs. The instructions I received is to put the collar on an hour before we go and leave it on an hour after we return. Then remove, place in ziploc bag in fridge. Good up to 3 months. Cost around 20 dollars. Bought it at vets office.