Review on 🌊 2-Pack PH Water Digital Tester Meter with TDS EC PPM Pen - Ideal for Household Drinking, Pool, and Aquarium Uses by Justin Guldin

I wanted to calibrate the PH meter so I could start using it for water testing. I bought distilled water and put in 3 clean glasses with 250ml distilled water each. and then PH is packed into each cup. The first cup is calibrated to the right amount. the second cup is not calibrated at all, and then the third cup is calibrated against what the first cup registered. With each replacement I cleaned the contact with distilled water. I started the process again with different results. The 3rd cup registers the measurements of the first cup, the first cup registers the measurements of the second cup, and then when you clean it and hold it in the air, it registers a non-stop fluctuation in reading.