[Bill]

Don
Very interesting reading. I've always been curious about the size of air spaces in the head. Since you made 80-100 ml of solution disappear, they are at least twice as big as I thought. I've used a method similar to yours to put saline solution in my sinuses and ears before diving for the last year or two. I only used one shot because I felt that it would drain out when I stood up and be forced out during warm up dives. Next time I'll try more.
I tried flushing with sea water (2.8% here) but it made sinus clearing more difficult. For a solution, I just use sea water diluted with tap water to about 1%. Five minutes of microwave radiation and a filter should take care of most bugs, I hope.
Aloha
Bill