YSI 63 - Manual (Page 25)

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6.3 pH Sensor Storage
For short term storage between measurements in the field (up to one week), place the probe in
the transport chamber in the side of the instrument case. Make sure that the sponge inside the
chamber is wet (tap water).
For long term storage (over one week), place the probe in the storage bottle (provided)
containing a mixture of 50% pH 4 buffer and 50% 1.5M KCl. This will assure the fastest
possible pH response. If this mixture is not available, storage in tap water is the next best choice.
Do NOT store the probe dry or in distilled or deionized water.
NOTE: After storage in the pH 4/KCl solution described above, place the probe in the transport
chamber in the side of the instrument case or soak the probe in pH 7 buffer for 5 to 10 minutes
allowing it to acclimate before calibrating.
If the probe has been inadvertently left in air and the reference electrode junction has dried out,
good function can usually be restored by soaking the probe in the pH 4/KCl solution described
above.
6.4 Conductivity Sensor Cleaning
The single most important requirement for accurate and reproducible results in conductivity
measurement is a clean cell. A dirty cell will change the conductivity of a solution by
contaminating it.
NOTE: Always rinse the conductivity cell with clean water after each use.
To clean the conductivity cell:
1. Dip the cell in cleaning solution and agitate for two to three minutes. Any one of the foaming
acid tile cleaners, such as Dow Chemical Bathroom Cleaner, will clean the cell adequately.
When a stronger cleaning preparation is required, use a solution of 1:1 isopropyl alcohol and
one molar (1 M) hydrochloric acid (HCl). Remove the cell from the cleaning solution.
2. Use the nylon brush (supplied) to dislodge any contaminants from inside the electrode
chamber.
3. Repeat steps one and two until the cell is completely clean. Rinse the cell thoroughly in
deionized, or clean tap water.