I happen to be an expert in the thrushy feet department

Borax is a wonderful tool for curing thrush and canker. Its a very old laundry soap that is drying and quite concentrated. When My horse had terrible thrush we scrubbed his feet once a day with borax and soaked them with borax. worked better than any other crappy thrush medication. Keep it simple, and if your horse has thrush have a good look at the overall condition and shape of the foot and frog. Bad shoeing, bad feet = Lameness & Thrush!!!