pH 4.0 calibration solutions - a must in every grower's toolbox
 
Type: A clean probe is an accurate probe
Bluelab pH Pen Cleaning Instructions
Bluelab pH & Soil pH Probe Cleaning Instructions
Bluelab Soil pH Pen Cleaning Instructions
pH 4.0 calibration solution MSDS
 
Contains 500 ml/16.9 fl oz 
Boost your pH products’ longevity with regular cleaning and calibration