I use a half cup (4 ounces) of distilled water (my tap water is shyte - has chloramines and who knows what in it), a quarter teaspoon of Sea Salt and a quarter teaspoon of baking soda and then add about 8 drops of tea tree oil and a capsule (about 250 mg) of sea buckthorn oil. Tea tree oil is antiMICROBIAL so it's good against bacteria AND fungus. Don't go TOO strong with it - too much tea tree oil may be harmful to the ear. The sea buckthorn I added in since I continually had a "raw" feeling spot way up in my sinuses. Sea buckthorn helps support mucus membranes in general, a pdf of Finnish research on sea buckthorn: http://seabuckthorn.com/files/sea_buckthorn%20women.pdf
I find the sea buckthorn balances out the discomfort of the tea tree oil. Also, the raw feeling is GONE on the days I do this. I only started adding a whole capsule in this last month or so.
I want to put a plug in for Wally's Ear Oil here too. Finally greatly diminished some middle ear discomfort after using the ear oil all winter at night in the ear on whhich side I had the other issues. This ties into my sinuses because the more congested I get the more my eustachian blocks up and the less my middle ear can drain or whatever. - bd