no refilling required

3000 hours of continuous use (batteries included)

Why Calibrate Regularly

wastewater analysis

Bluelab pH 4.0 Calibration Solution – 250 ml / 8.4 fl oz water quality bench meter no refilling requiredpH 4. 0 calibration solution a must in every grower's toolbox Contains 1 bottle 250 ml 8. 4 fl oz Boost your pH products longevity with regular cleaning and calibration Bluelab pH 4. 0 Calibration Solution ensures accurate pH meter readings with lab grade precision. This 250 ml bottle delivers consistent calibration for refractometers, pH meters, and water quality testing equipment. Essential for maintaining measurement accuracy in hydroponic systems,