Leaf Porometer Operator’s Manual
7. Care and Maintenance
69
agreement in humidity measurements between the two sen-
sors, or as nonsensical humidity values from one or both
sensor (e.g. >100%).
If you suspect that your leaf porometer has been affected by
chemical exposure, then the sensors can be re-conditioned to
return them to their natural state using the following procedure:
1. Remove the sensor head from the hand held readout unit.
2. Use the metal pin from the calibration kit to hold the leaf
clamp open.
3. Place the entire sensor head (and cable) into an oven with
good temperature control.
4. Bake the sensor head in dry heat at 80° C for at least 24
hours.
5. Remove the sensor head and let cool.
6. Re-hydrate the sensor head by exposing it to 70-80% rela-
tive humidity at 20-35° C for 12 hours. A 75% humidity
atmosphere can be conveniently generated by a saturated
NaCl solution. To hydrate with saturated NaCl, the
porometer head should be placed in a sealed container
above a slurry of NaCl (table salt is fine) and water.
There should be both liquid water and plentiful salt crys-
tals present in the slurry.
7. After hydration, the sensor should be left at ambient con-
ditions for 8 hours before calibrating the sensor. Please
note that re-conditioning the sensors will change the