Having two degrees in biology, I am perhaps too aware of microbes that can be passed from diver to diver via alternate air source regulators. This is one reason I advocate alternate air source drills that do not require "trading spit" to perform them. I advocate, in most training situations, especially recreational diving, using a separate alternate air source regulator with recreational length hose and utilizing your buddy to test the alternate air source to avoid spreading germs from one diver to another via saliva and mucous. Of course, in a true out of air emergency safely securing air to breath is of primary concern and worrying about germs is far down the list. Technical diving has different procedures, for different reasons, but even in this realm, I have to wonder whether sharing germs during training is wise.
I am not a fan of the alternate air source regulator such as Air 2 and I am amazed these are so wide spread in use. These not only require you to trade microbes while practicing out of air scenarios, but complicate them by requiring both donor and receiver to change regulators. The donor must breath and dump air from the same device which is in his/her mouth not overhead for dumping air. I used the Air 2 for a few decades but always switched to a standard octo when doing training. Now I just see them as an unnecessary gimmick. While some would argue it streamlines the scuba kit, this isn't true because the device is bulky and the hoses longer and thicker. Often these cost extra to service so it costs you over time.
I am not a fan of the alternate air source regulator such as Air 2 and I am amazed these are so wide spread in use. These not only require you to trade microbes while practicing out of air scenarios, but complicate them by requiring both donor and receiver to change regulators. The donor must breath and dump air from the same device which is in his/her mouth not overhead for dumping air. I used the Air 2 for a few decades but always switched to a standard octo when doing training. Now I just see them as an unnecessary gimmick. While some would argue it streamlines the scuba kit, this isn't true because the device is bulky and the hoses longer and thicker. Often these cost extra to service so it costs you over time.
But how can you be sure the regulators you are putting in your mouth during training or when renting are reasonably germ and virus free to begin with?
Ask!
Ask the provider how the regulators are sanitized. Your instructor or resort operator should be able to explain the sanitizing procedure which usually consists of soaking regulators in a commercial sanitizing solution and drying them thoroughly between uses. The truth is that more often than not, this is not done at all. Owning your own regulator is one solution to this problem, but even then it is a good idea to clean and sanitize your gear. Community rinse tanks are notoriously nasty, so use caution with these as well.