It should not be critical to have the calibration fluid at 25 deg C, assuming the Pinpoint has reasonable temperature compensation algorithms. You can test this just by calibrating at a higher temp and then letting the calibration cool and seeing the difference in measurement.
Note that the Pinpoint can take a few minutes to come to temperature equilibrium.
FWIW, I've never had to recalibrate mine. I've also had a different meter (Orion model 128) which is very expensive and cannot be calibrated (only checked). In the more than a decade that I've had it, it has not drifted at all, and always reads 53.8 mS/cm for a true 53 mS/cm standard.
So frequently calibration is not to be generally expected with a conductivity probe, at least if it is kept clean (I do not leave mine in the water between uses).
Note that the Pinpoint can take a few minutes to come to temperature equilibrium.
FWIW, I've never had to recalibrate mine. I've also had a different meter (Orion model 128) which is very expensive and cannot be calibrated (only checked). In the more than a decade that I've had it, it has not drifted at all, and always reads 53.8 mS/cm for a true 53 mS/cm standard.
So frequently calibration is not to be generally expected with a conductivity probe, at least if it is kept clean (I do not leave mine in the water between uses).
