Bluelab pH 4.0 Calibration Solution 20 ml Sachets
pH measuring equipment must be cleaned and calibrated regularly to ensure they are giving the user accurate readings. pHﾠinstruments areﾠcalibrated to pH7.0 first (buffer)ﾠthen to pH4.0 (slope). Bluelab's EC/CF equipment does not need calibrating as they are all factory calibrated. The CF27.7 (EC2.77)ﾠsolution is used as a reference or checking solutionﾠto ensure you have adequately cleaned the EC/CF probe.