Sorry for the late reply, but I just saw the post.
Our previous lab used to have issues with dirty ears. Our vet gave us a choice of either the solution they have for sale or we could make our own which he called the WAV mix.
It is equal parts of vinegar, alcohol, and water. The vinegar take care of any yeast problem and the alcohol was to assist in drying. The water was just the flushing fluid.
Much cheaper solution and usually have all the ingredient available no matter where you are.
Glad you got it solved.
Dave