The ideal combination to force the fungi into dormancy is a combination of Cider Vinegar with Alcohol and a herb called Thuja along with the Bach Flower Remedy Crab Apple.
In combination this mix will dry out the canal and leave a fine layer of acetic acid (from the Vinegar) on the skin of the canal along with a residue of this herb (Thuja). This situation is definitely not conducive to fungal growth so it becomes dormant and can remain so for years. Every time your dog gets some fresh water in the ear you can repeat the treatment for a few days and drive the fungal back into dormancy.
A few drops in the affected ear once daily.
For External Animal Use Only
McDowell's staff Herbalists can not diagnose you or your companions disease or illness. What they can do is offer a herbal program to assist with healing, after you have had advice from your doctor or specialist. If you have unexplained pain or symptoms, seek medical advice.