Bests & Worsts Reviews from Amazon

I invested in an indoor air quality sensor, because I wanted to track how much seasonal wildfire smoke makes it into the house and how well the air filters are doing removing the particulates. After getting this humidifier the Air Quality Index (AQI) readings started suddenly and inexplicably spiking up into yellow in our house each night. The new factor was running this humidifier at night. Humidity doesn't affect the readings on the sensor we own, but I suspected some correlation. I searched the web and found information about "Ultrasonic Humidifiers and Indoor Air Quality". This matched what we already observed. We were filling it with clean (I believe) Rocky Mountain municipal tap water. However, whatever is in our water that this thing is atomizing into the air was detected and flagged by our air quality sensor as something we perhaps shouldn't be breathing. Our AQI sensors and humidifier are many rooms apart in opposite sides of a 3K square foot house with high ceilings (lots of air volume). We, on the other hand, are sleeping next to this humidifier. Water that is perfectly safe for drinking does not guarantee something safe for vaping. Steam humidifiers, evaporative furnace humidifiers, and things like shower steam don't make the calcium and various minerals, or whatever else, that is in your water absorbable into your lungs like ultrasonic humidifiers do. Absorbing whatever is in your tap water into your lungs might possibly be benign. However, you probably shouldn't be experimenting on yourself. This is not specific to this brand, this is something all ultrasonic humidifiers do. If we didn't have the AQI sensor, we wouldn't have suspected anything. They say here, "Use the water as pure as possible". I see now why they say that and that they REALLY mean it. I strongly suggest you use distilled water in this thing. That should be safe. The LED was crazy bright for bedroom use. I put a circular self-adhesive Velcro pad over the light to allow the ability to sleep near this thing. It makes occasional gurgling sounds as the reservoir drains into the tank. Not a big problem.