DIY Air Humidifier (floater for mist maker)

This model fits ultrasonic mist makers with a diameter of up to 46mm like this one: https://amzn.eu/d/9iJLRSI An ultrasonic mist makers are great to watch and a great way to building diy air humidifiers. But there is a very noticeable disadvantage to them:You have to place them at a certain depth under water or they don't work well. Why is that an issue?If the water level in your container drops by more than 2-3 cm, the device won't function properly because it's not s