Question about Stadler Form Oskar

I have 2 questions: 1. after starting up the appliance in the living room, it does not run (except in continuous operation). Does this mean that the humidity is really already too high? I measured just under 40% a few days ago. Or is it also due to the location? It is currently on the floor against the wall next to the window front. Question 2: According to the manufacturer, it doesn't matter, but should it be distilled water? The water hardness in the region is 25-27. There are different opinions on the Internet, and there is also talk of mixing water (half/half). As I should clean the humidifier every 2 weeks anyway, I can also remove the limescale residue.