Not quiet per se, except in a relative sense, but definitely "not noisy"
Just playing - they're the bomb. Mine is in my bedroom and I'm really intolerant of extraneous noise and particularly machinery when I'm trying to sleep as I prefer my respites to be lyric. Can't speak to the larger models but the AL-14A and its smaller kin are first-rate. It's audible, but in a quiet way. The only reason I've still got my own "menagerie" of air pumps is because I haven't got a spare set of diaphragms yet for this one. They add $30 to the price but I believe Big Al's or someone has a discounted package deal ($129.00?) that may or may not come with a manifold. The price I gave before is from Ken's and he claimed a few months ago to have replacement diaphragms but haven't been able to get him on the phone since to get a price or to verify. Bottom line is whatever you're collectively using now is likely at least twice as noisy as the Alita will be. I bought five or six different kinds of "quiet" air pumps at one time (Rena, Whisper, Dolphin, Airpod, etc.) to compare and was either disappointed by their output and/or noise and/or crap quality (Whisper). Anyway, once you get up to a certain number of tanks the "one pump fits all" approach is the only one that makes any sense in a number of ways. As the owner of BMW Boxer and a former machinist I have a soft spot for things that are built and work well, so yeah, jump on it. If you're disappointed I or someone else will surely take it off your hands at cost.
