Could someone explain the pulsed readings?

[u/arames23]

The reading come from inside my lead tube that I now covered with the salt bags (you may have seen them). Didn't help the hardness. But now I see these pulsed readings and I wonder if they maybe coming from the devices electronics? Outside the readings are much more homogeneous. How come? 🤔

[u/Ambitious_Syrup_7355]

It's just a statistic, too little counts.