How many germs restrain the cartridges, I do not know, and not what is going on with the silver addition in coming. I would not use such things in the way my stay in Freiburg, where there are relatively soft water. But in Waldshut I'm very happy with it: While earlier black after a few hours as in boiled milk a skin formed, which could be partially pull his finger, my tea is now, thanks to the filter cartridges, again tea. And the kettle I have not descaled every two to three weeks, but no more than twice a year. Conclusion: Find out about the lime content of your water and you decide on whether the use of filter cartridges worth. I for one do not want to miss.