We're using Advantix as well and it's working great for Jimi
We've never had any fleas or ticks
It's also pretty reasonable, only $10/month from my vet.
Just a word of caution though if you have a cat - it is highly toxic to cats so you must keep your dog & cat separated for 2 hours after applying.
hope you find something that works.
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♪ Jimi | Marshall | Hendrix ♫
"When the power of love overcomes the love of power, the world shall know peace." - Hendrix