This! Don't use an ultrasonic humidifier unless you fill it with distilled water. Tap water will just create a ton of white dust everywhere.
If you absolutely need more humidity in your home, get something like the Venta LW45 which has a half-submerged rotating disk and blows air over the still wet surface. Works with tap water (requires regular cleaning and a special additive).
"The case against ultrasonic humidifiers."
https://dynomight.net/humidifiers/