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Routine maintenance and storage of Myron Ultrapen PT5 DO pens.

Question: How do i store my Myron Ultrapen PT5 when not in use?

Answer: To preserve the life of the sensor, the PT5 is shipped dry (with no electrolyte solution in the sensor). Follow the instructions for sensor setup prior to use. If you need to store the
PT5 after use, follow the instructions below.


Short Term storage:
The sensor should be kept moist with the hydration cap containing a sponge moistened
with DI, RO or distilled water.
Long-term storage:
After setup, the zinc anode will be immersed in electrolyte solution and will be
continuously oxidizing, even while unused. For long-term storage it is best to remove the
electrolyte, rinse the sensor and membrane cap, and store it dry. You should also remove
the battery from the PT5.
To prepare the sensor for long term storage:
1. Remove the membrane cap by turning it counterclockwise.
2. Rinse the membrane cap thoroughly with DI, RO, or distilled water, gently pat it dry with a soft lint-free cloth, and place it to the side. BE CAREFUL not to harm the membrane.
3. Discard all the electrolyte solution from the sensor’s electrolyte well.
4. Fill a syringe with DI, RO, or distilled water.
5. Holding the open sensor sideways or upside down over a sink insert the syringe tip into one of the four openings of the sensor body and thoroughly flush the electrolyte
well with DI, RO or distilled water. Shake all the water out of the sensor, and repeat 3-4 times.
6. Shake all the water from the sensor, pat dry with a soft lint-free cloth, and allow the sensor to completely dry out.
7. Remove the sponge from the hydration cap.
8. Rinse the hydration cap with clean water then dry it with a soft lint-free cloth.
9. Once the sensor, membrane cap, and hydration cap are thoroughly dry, reinstall the membrane cap and hydration cap.
• The foam from the hydration cap should be stored separately, as any moisture in the sensor will promote oxidation.
10. Remove the battery from the PT5.
11. Store the PT5 in a cool dry location.

2865-056NOTE: When you are ready to use the PT5 after long-term storage, follow the sensor
setup instructions. Verify the membrane is not torn or otherwise damaged.

If oxidation is present inside the sensor, clean the sensor prior to sensor setup; see operating instructions

Routine Maintenance of the Membrane for optimal performance

1. After each use ALWAYS rinse the DO sensor with DI, RO, or distilled water and then carefully blot the sensor membrane with a soft, clean cloth or tissue to remove any water drops.

2. ALWAYS replace the hydration cap on the DO sensor after each use.

3. Do not drop, throw, or otherwise strike the PT5. This voids the warranty.

4. Do not store the PT5 in a location where the ambient temperatures exceed its Operating/Storage Temperature limits.

5. DO NOT remove the DO sensor membrane except to replace it with a new membrane or to replace / refill the electrolyte. • Unnecessarily removing and replacing the same membrane can degrade the quality of the DO measurements.


The PT5 display has an indicator that depicts the PT5’s battery charge level. When the charge level indicator only shows one bar, immediately replace the battery with a new N type battery.

1. In a CLEAN DRY place unscrew the battery cap in a counterclockwise motion.

2. Slide the cap and battery housing out of the PT5.

3. Remove the depleted battery from its housing.

4. Insert a new battery into the battery housing oriented with the negative end touching the spring.

5. Align the groove along the battery housing with the guide bump inside the PT5 case and slide the battery housing back in.

6. Screw the battery cap back on in a clockwise direction. Do not over tighten.


• Always Replace the sensor dry and fill with electrolyte after installation.

• Follow the instructions that come with your replacement sensor.

• Only remove/replace the DO sensor in a CLEAN and DRY environment.

To remove the DO sensor:

1. Remove the hydration cap.

2. Remove the membrane cap and empty the electrolyte well of all electrolyte.

3. Make sure the PT5 (including the DO sensor) is clean and dry.

4. Loosen the battery tray (to allow pressure equalization).

5. Firmly grasp the DO sensor body and slowly pull the sensor out. DO NOT allow electrolyte into the body of the PT5.

6. To install a new DO sensor: Line up the alignment tabs on the DO sensor with the alignment slots on the PT5 unit.Gently push the DO sensor into position, and then close the battery cap.

• When excess bubbles have formed inside the electrolyte well, you should refill the electrolyte solution. Minimizing air
bubbles inside the electrolyte well will improve accuracy.
• Always avoid touching the membrane.
• When too many white zinc oxide particles have formed inside the electrolyte solution, or readings are not as they
should be, replace the electrolyte solution.
• If you get erroneous readings after changing the membrane cap and performing the proper calibration, completely change the DO sensor electrolyte solution.

Full instructions can be followed regarding the  electrolyte replacement procedure.