Review on Xiaomi Smart Antibacterial Humidifier (ZNJSQ01DEM / SKV4140GL), white by Micha Kowalski Czajo ᠌

Because impurities are split with water during ultrasound evaporation, which does not occur naturally, it is best to use distilled water if your water is hard so that there is no slight plaque on objects in a humidifier's vicinity or impurities residues on the filter of the device itself (though, of course, it is still worth rinsing it every few weeks). In general, it is better to look towards a humidifier from Xiaomi with a drum that evaporates water naturally if the quality of the water in your home raises many concerns. There won't be any impurities in the steam, and the drum is simpler to clean in it. If you're buying, keep this in mind;)