Yes you are correct. To do it correctly you should also calibrate two points above and below your intended range. It is not good to calibrate at 7 when all your readings are going to fall in the 12 range. The other measurement concerns repeatability and need to be sure you can repeat three or four times (within the accuracy of the instrument) the same result. These two calibrations will give accuracy and repeatability necessary to be exact in your measurements. Keep a close eye in the temperature and homogeneity of the solution (avoid entrapped gases, etc.) Frank
From: Neville Munn Sent: Sunday, February 20, 2011 3:44 AM To: [email protected] Subject: RE: CS>pH calibration fluid? I believe I've found the answer to my question. If only calibrating one point, the meter won't recognise accurately acidity *or* alkalinity if no other point is used. At least a two point calibration would be required so the meter has a 'range' to work with and knows *what* to measure...Yes/No? N. -------------------------------------------------------------------------------- From: [email protected] To: [email protected] Date: Sun, 20 Feb 2011 11:56:52 +1100 Subject: CS>pH calibration fluid? Can someone help me out here re: specifically a *single point* calibration? If one does not need to calibrate below base 7 or below in the acidic range, is a buffer solution of 7.01 adequate? I know one can calibrate to determine ranges between two desired figures, but using two buffer solutions would only be required if measuring both adicity *and* alkalinity would it not? If measuring *above* 7.0 only, or in the alkaline range, I would assume two calibration points would not be necessary as the reading would/should never go below 7 in this instance...Yes/No? Thanks N.
