Humidipak calibration pack question

[strife]

Grabbed a 75% calibration pack at the B&M last week and checked 3 suspect hygrometers (2 digital, 1 analog) separately. Each measured 77. Could they all be off 2% or might it be the pack? I know it doesn't seem like much but it has me head scratchin. :scratchhe

 

[twenty5]

From what I understand, those things are dead on. You bought it sealed right?

 

[strife]

Yeah it was sealed. Now the question is should I bother recalibrating or just subtract 2!!

 

[Starz26]

I think I should pick up one of those. I did the salt test and both the hydrometers read 68% after 4 hours...maybe not enough water....

 

[Jfire]

Salt tests are more accurate w 24+ hours of time. Humipacks I think if I remember are accurate to +-1%rh. Ron will prob be in to chime soon.

 

[RonC]

trust the calibration kit. it is 100% dead on.