Q:Why the tester shows zero and never changes?
A: This situation is because the chip is loose.don’t worry and just follow the step:
Step: Turn off the tester and open the battery cover,then press the battery in,check the chip is reset or not.If the chip in the right position, you can test it in the water.
Q:Why the temperature recordings not accurate?
A: The reading of TDS is affected by temperature, so the tester need the temperature compensation for the accurate reading.Here are some suggestions for you how to use it in the below picture.
Notes: To make sure the reading of this Digital TDS Tester Pen whether correct, It is best to buy pure water or distilled water to test, because the two waters have a fixed value of -0, But the pool/SPA water does not have a fixed value.