The only reason that this review doesn’t rate a 4+ is is even with that absolute minimum amount of water in the reservoir and minimal inhalation water overflows the “the wet side” into the “dry side” and completely soaking the filter.
If you will allow me a minor design suggestion that might help alleviate the over flowing issues.
I’m not an engineer by any stretch the imagination but I am a former firefighter and a part of some of our training involved responding to and mitigating hazardous materials situations.
One of the way that we mitigate further contamination of a fresh water source is to basically make either the liquid contaminant, or the freshwater source do what we want which in one instance that applies here is to create a S (or z, or M, or N) shape in the air path. That way even if you get overflow into the first leg of whatever of the above shapes, it will start getting more trapped with each successive bend in the shape. Of course you would eventually start getting diminishing returns for each successive leg, but I think that using a simple “N, S or Z” shape should reduce any overflow actually making it to the filter by >90%. That of course would all depend on water level in the reservoir and breath strength.
Please forgive me if I’ve overstepped, but I just thought that it might be a beneficial improvement to the design, which currently could best be described as a simple “u” shape.
The current design even supports an S or even an M shaped air path…