Review on 📈 Wiztech Digital PH Meter with ATC: 3 in 1 PH TDS Temp - Accurate Pocket-size PH Tester 0.00-14.00 PH Measurement Range by Michael Reynolds

Standard pH varies from 0.2 to 0.3 I tried several bottled test solutions and the numbers were far from accurate, especially for a PPM meter. main problem. You can't actually calibrate this block. The instructions say to mix the dry packs that come with it, or to buy special pH 9.18, 6.86, and 4.00 solutions. You dip the pen into the solution and wait for the reading to stabilize. Then press and hold CAL. It then flashes any readings it has as if it is doing something. I had it in solutions 4 and 7 but it was either too high or too low. All you can do is hold down the CAL button and then you'll get false readings. That's all. You do not have the option to increase or decrease the reading to calibrate the solution. It's a piece of junk. Just buy a quality brand or cheap little yellow pens that only measure pH.