Regardless of what these meds promotes, they're not 100% full proof. I use Advantix II (supposedly one of the best)for both Magnus/Zoey and at the start of summer, I found a tick on Magnus almost every day after our walk. Zoey, not so much but I carry her for most of the walk.
You might want to consider trying Advantix and see if that works better in your area. But I suggest just checking him everyday or at least several times a week with your fingers. Check EVERYWHERE! I've found those parasites in some of places where I didn't even think to check before. It doesn't take long and better safe then sorry. |