How to Calibrate a TDS Meter
TDS stands for total dissolved solids. A TDS meter is a probe that consists of two metal probes that are inserted into water or hydroponic solutions to measure the amount of salt and minerals that are in the liquid. A TDS meter must be calibrated regularly to continue giving an accurate reading. If the meter is used every day, it should be calibrated once a week. If it is used less often, it should be calibrated once every two to three weeks. As battery life decreases, the meter loses calibration.