I’m trying to mainly base a DIY humidifier on this [instruction](httpsp://www.hackster.io/abc15634/diy-a-simple-automatic-humidifier-61458f) But I’d like to make sure no germs or microbes are in the water and spreading in the air,as well as no white dust ( minerals/ limestone) being spread out with the mist, I was thinking I could somehow use a UV light, but don’t know how, how big and strong should the light be? should it be immersed in the water? For the white dust, I guess I could just buy a Brita bottle like this and fill the humidifier with water from it, right?

If I already have your attention, another question, in this video, why is the little tube out from the piezo element back into the lamp necessary? Wouldn’t the mist still be possible to happen through and out the water?