1. The storage buffer solution must completely cover the sensor tip when on its side or upside down. Keep the storage vial filled to the top.
2. The sensor must be rinsed and blotted dry between uses.
3. The sensor has a glass tip; it can break.
4. The pH sensors do not need to warm-up. They should instantly read around 4 because the storage buffer is at pH 4.
   1. Connect the Go!Link to your computer using the USB cable.
   2. Using Logger Pro, open the specific .cmbl file needed for the exercise.
   3. If the initial reading is not hovering around 4, skip to section B below.

B. Calibration

If you find that the initial reading is under or over 4 when you first plug in the sensor and open Logger Pro, then follow the procedure below.

1. Go to the Tool Bar and select ‘Experiment’ > ‘Calibration’ > ‘Go!Link: pH.
2. The ‘Calibrate’ tab will be open in the window that pops up.
3. Follow the 2-point calibration procedure:
   1. Remove the sensor from the storage vial.
   2. Place sensor in buffer standard 4.
   3. Click on the 'Calibrate Now' button.
   4. Type 4 in the cell of the 'Reading 1' section.
   5. Click on ‘Keep’.
   6. Rinse the tip with a wash bottle and blot dry with a Kimwipe.
   7. Place sensor in buffer standard 7.
   8. Type 7 in the cell of the 'Reading 2' section.
   9. Click on ‘Keep’.
   10. Rinse the tip with a wash bottle and blot dry with a Kimwipe.
   11. Place the sensor back in the storage vial that is filled with storage buffer.
   12. Once the calibration is complete click on ‘Done’.
4. The ‘Current Calibration:’ drop down will show ‘pH <Not Saved>’
5. Go back to the Tool Bar and select ‘Experiment’ > ‘Calibration’ > ‘Go!Link: pH’.
6. Once the window opens select the ‘Calibration Storage’ tab.
7. Follow the calibration storage procedure:
   1. Make sure that the ‘Current Calibration:’ drop down shows ‘pH <Not Saved>’.
   2. Click on ‘Set Sensor Calibration’. A new window will open.
   3. Click on ‘Set’, ‘Done’, ‘Write’.
8. Unplug the pH sensor from the Go!Link and then plug it in again. If the Logger Pro reading window does not read around 4 the calibration storage procedure did not work. Repeat section B.

CO² Sensor

 A. Use

1. Make sure the switch on the sensor is set to LOW 0 - 10,000ppm.
2. The CO₂ sensors need to warm-up for 45 seconds to 2 minutes. They are ready to use once they read 400 ±100 ppm and the reading is somewhat stable (doesn’t jump around too much).
   1. Connect the Go!Link to your computer using the USB cable.
   2. Place the CO₂ gas sensor upright in a dry beaker and then plug it into the Go!Link.
   3. Using Logger Pro, open the specific .cmbl file needed for the exercise.
   4. Wait between 45 seconds to 2 minutes for the reading to reach 400 ±100 ppm.
   5. If the reading is under 300 or over 500, skip to section B below.
3. Between runs keep the sensor sitting upright in a dry beaker.
4. Do not blow on the sensor shaft.
5. Do not get the sensor wet. It is meant to be used only with air.

 B. Calibration

The sensors were checked to make sure they read 400 ±100 ppm. However, if you find that after you have completed steps 1-4 from section A, the readings are under 300 OR over 500 go through the calibration procedure.

1. Hold the sensor upright.
2. Plug the sensor into the Go!Link.
3. Open Logger Pro.
4. Wait 2 minutes to allow the sensor to warm-up.
5. After 2 minutes, hold the sensor calibration button down (found on side of sensor) until the spot below the button flashes a red/orange light
6. After about 30 seconds, the reading should stabilize at a value of approximately 400 ±100 ppm. If the reading is under 300 OR over 500, simply press the button again to repeat the process. Note: If the red light stays on solid, you have held the button too long. In this case, wait for it to go off and press it again, releasing as soon as it begins to flash.
7. Close and Re-open Logger Pro.
8. Wait 2 minutes and then check that the calibration worked and the reading is still 400 ±100 ppm.

O² Sensor 

A. Use

1. Keep upright at ALL times.
2. Place in a reaction chamber ONLY during a run.
3. Between runs keep the sensor sitting upright in a DRY BEAKER.
4. Do not get the sensor wet. It is meant to be used only with air.
5. Do not blow on the sensor shaft.
6. The O₂ sensors do not need to warm-up. They should instantly read 20.9 ±1.0%.
   1. Connect the Go!Link to your computer using the USB cable.
   2. Place the CO₂ gas sensor upright in a dry beaker and then plug it into the Go!Link.
   3. Using Logger Pro, open the specific .cmbl file needed for the exercise.
   4. If the initial reading is under 19.0% or Over 22%, skip to section B below.

B. Calibration

The sensors were checked to make sure they were in the 0-20.9% O₂ gas range. However, if you find that the reading is significantly lower than 20.9% when you first plug in the sensor and open Logger Pro, then follow the procedure below.

1. 1. Go to the Tool Bar and select ‘Experiment’ > ‘Calibration’ > ‘Go!Link: 1 Oxygen Gas’.
   2. The ‘Calibrate’ tab will be open in the window that pops up.
   3. Follow the 2-point calibration procedure:
      1. While holding the calibration button down (found on side of sensor) enter a value of 0.
      2. Click on ‘Keep’.
      3. Release the calibration button.
      4. Enter a value of 20.9% oxygen.
      5. Click on ‘Keep’.
      6. The Logger Pro reading window should show the calibration.
   4. Once the calibration is complete click on ‘Done’. The ‘Current Calibration:’ drop down will show ‘Oxygen Gas % <Not Saved>’
   5. Go back to the Tool Bar and select ‘Experiment’ > ‘Calibration’ > ‘Go!Link: 1 Oxygen Gas’.
   6. Once the window opens select the ‘Calibration Storage’ tab.
   7. Follow the calibration storage procedure:
      1. Make sure that the ‘Current Calibration:’ drop down shows ‘Oxygen Gas % <Not Saved>’.
      2. Click on ‘Set Sensor Calibration’. A new window will open.
      3. Click on ‘Set’, ‘Done’, ‘Write’.
   8. Unplug the O₂ sensor from the Go!Link and then plug it in again. If the Logger Pro reading window does not read around 20.9%, the calibration storage procedure did not work. Repeat section B.