It leaves gum deposits

The Biopretta-hygiene does what it should. The wheels of our Beurer Airwasher calcify hardly and the water does not get moldy. For two stars. Unfortunately, the device is coated use above the water level (fan, motor etc.) with a resinous, sticky layer after 3 months. The hygiene probably contains oily components which settle in the air flow there, gum up and can not be removed with normal detergents. Pretty disgusting! Hygiene is different! I do not even want to think about how the interior of the humidifier will look after a few heating seasons. The unit will be ruined sooner or later. Conclusion: Once again saved in the wrong place.