Question about Xiaomi Mi Smart Antibacterial

I suspect a defect in the existing fan. The warranty could help, or if that is not possible, a spare part, available cheaply from Aliexpress, for example, could also help. It is also possible that minerals in the water used cause deposits to form in the ultrasonic atomiser.

I generally recommend only filtered water for ultrasonic nebulisers, which I can quickly get together with a simple water filter, for example. Or alternatively the humidifier models that evaporate the water with rotating discs, e.g. this one:

Xiaomi Smartmi Evaporative (15 m²)

They don't leave any white marks on furniture and can also be used without any problems next to a Xiaomi or other air purifier.