How does furring occur in kettles from hard water?

Hard water contains high levels of minerals such as magnesium and calcium and can be a real pain to remove if left untreated. When hard water is boiled in an electric kettle, these minerals do not evaporate like the water does but instead remains in the kettle.

you did not give any options thus this is the best answer i can give to you with this little information you have given

> they are both natural and not man made

> they can be tracked and predicted by the right tools

-love shrooms

the answer is 0.42 is that is an option. this question provides no info