The meter is working correctly. I just calibrated and tested it.
I washed nothing with the water and used only some alder cones, which i used before, too. So I exclude them.
My fingers, yes there might have been some sweat or tap water sticking on, but does that effect 160 litre?
I never had this before, but shurely used my hands all the time 😉
Know I replaced all of the water and everything seem perfect again. But i will go on with the measure the next weeks.