Why Kärcher recommends NOT putting more than 50% distilled water in the tank! It is said that this could damage the proper functioning of the product... Sorry... the worst problem with this type of product is scaling (limescale)... Kärcher certainly recommends descaling the tank regularly by leaving a solution designed for this to stand for 8 hours. After that, you have to turn the appliance upside down to empty the tank containing the descaler... a "rather sporty" operation, I might add ;) I'd be interested to hear what you have to say about this. Thanks to all of you.