hygrometer calibration kit contradiction

[newbie1]

i bought a digital hygrometer and a humidipak calibration kit. on the humidipak it says to calibrate it to the number in the upper right hand corner, which is 75.5%. but the little packet insider the humidipak says "75% relative humidity." Also, the instructions for calibrating the hygrometer that came with the hygrometer says it should be calibrated to 75% relative humidity.

should i calibrate it to 75% or 75.5% rH?

[madurolover]

Originally Posted by newbie1

i bought a digital hygrometer and a humidipak calibration kit. on the humidipak it says to calibrate it to the number in the upper right hand corner, which is 75.5%. but the little packet insider the humidipak says "75% relative humidity." Also, the instructions for calibrating the hygrometer that came with the hygrometer says it should be calibrated to 75% relative humidity.

should i calibrate it to 75% or 75.5% rH?

1/2 of a percent will make absolutely no difference.

[JCK]

Does you hygrometer measure to tenth of a degree? none of mine do

[e-man]

Most digital hygrometers are rated + or - 2%. These aren't high quality scientific instruments...they're made in China. Go buy two units an see if they read anywhere close to one another.

But to answer your original question: Table salt regulates at 75.5% (in a sealed container), so a calibration pack should do the same.