What's worse than losing a piece of dive gear, worse than a day of uncooperative weather? Getting an ear infection during a dive vacation. An ear infection can keep a diver unhappily grounded for days. Worse, it seems to be most common to get ear infections during dive vacations, when divers are exposed to foreign bacteria or have weakened immune systems caused by travel and exhaustion. I am not a doctor, so take this advise with a grain of salt, but divers have been brewing a home remedy to prevent ear infections for years, and it's called ear beer.
Divers can use ear beer as a preventive measure after any dive. Ear beer helps to prevent infections in two ways, it drys out the diver's ears, and it creates an acidic pH that kills off most types of bacteria that cause ear infections. This said, some environments are more likely to cause ear infections than others – and freshwater dives appear to be the worst. Freshwater dive environments seem to be more hospitable to bacteria, so definitely plan on using ear beer after dives in lakes, rivers, and freshwater caves.