Hi Marie
What does the gunk look like and what does it smell like? If you think it might be yeast, then the humidity and dampness definitely affects it. The type of yeast that is usually found in ears is not known to be sugar fed like systemic yeast, so not feeding sugars will not necessarily knock it out completely. It helps when you have a dog that is sensitive to grains, because the grain sensitivity causes skin problems, which causes the skin to over produce oil, which feeds this particular yeast. This yeast likes warm moist non acidic environments all of which probably describe Boones ears.
What I would do is make some swimmers ear solution, 1 part vinegar and 1 part rubbing alcohol, and after you clean his ears, fill the ear canal half way with that, insert a cotton ball, gently massage the base of the ear, use the cotton ball to absorb any extra solution then wipe down the rest of the inner flap of the ear, make sure you get inside that little fold of skin along the back edge of the earflap. Repeat this every time you clean his ears, while he is showing signs. Then do it twice weekly and after every swim or bath for another month. Then do it weekly and after swims or baths for another month. Then whenever you do anything that gets his ears wet, bathing, swimming.
The swimmers ear solution acidifies and dries which makes it a hostile environment for a lot of the bacteria that like to grow in ears too. If there is any raw or broken skin in the ear, it stings like the dickens.
I hope this helps.
