Crew;1038570 wrote: NH3 is going to go airborne pretty much 100% of the time unless you stop it from doing so (keeping it in a gas container, for example). The problem with ammonia in your tank isn't going to be coming from ammonia gas. It's extremely difficult to contain, and on the off chance that you have it in your house, it's escaping pretty quickly pretty much straight up through your ceiling. There is pretty much nothing you could do in your house to cause a serious ammonia build up that you wouldn't immediately notice, so I wouldn't worry about that.
The issue very well could have come from ammonium hydroxide (household ammonia, windex, etc) although still unlikely in my opinion to have been caused by an airborne issue unless that issue was overspray (spraying windex near the tank, for example). Ammonium Hydroxide isn't going to evaporate Ammonium Hydroxide - it's going to evaporate Ammonia gas (NH3) and water vapor. But I wouldn't worry about them recombining in the air or in your tank. NH3 has an extremely low boiling point and is pretty much rocketing out of ammonium hydroxide the second it gets the chance. It's not going to recombine with any vapor that it comes across as it floats up either unless you have a serious source of gas or a serious source of water vapor (the aquarium would have to be huge).
In laymen's terms - if you opened a household bottle of Ammonia (ammonia hydroxide), it wouldn't take long before you had a bottle of water with some scents or dyes added and the nh3 was long gone.
Crew and Russ thank you for taking the time to explain the process.