Review on Digital Water Testing Kit - Ruolan Lab pH Meter, TDS and PPM Tester for Hydroponics and Water Analysis by Eh Pyaw Paw ᠌

Here in the reviews it was written that he comes calibrated. No, not calibrated at all. The passport indicates the calibration process with three powders, two are available (but the seller has nothing to do with it, even with Ali it comes with two powders, 92022 is missing). Look at YouTube videos about its calibration and storage (storage is also not easy). When measured directly in the aquarium, it shows some strange values. I collect water from the aquarium into a measuring cup from under the tests of the nilpa in the cup shows intelligible values. I don’t know how people in YouTube videos show it right in the aquarium.