Temperature and Dissolved Oxygen

Instructions for taking temperature and dissolved oxygen measurements

The Temperature and Dissolved Oxygen meters are available for volunteer use from a number of Soil and Water Conservation Districts

Temperature and oxygen profiles should generally be made from the deepest water depths in your lake. You will have to anchor your boat, otherwise drift will cause inaccurate depth measurements.

  1. Turn on meter and calibrate according to instructions. **The meter must be turned on for 20 minutes prior to calibration to allow the electronics to stabilize.
  2. Calibrate the meter according to the enclosed directions. **Make sure that the internal sponge in the calibration chamber is moist with distilled water. You will need to know the approximate altitude in order to complete calibration. As long as you are using distilled water the conductivity should be zero.
  3. Once calibrated, remove probe from calibration/storage chamber.
  4. Lower probe into water to desired depth.
  5. (Always start measurements with the probe at just below the water’s surface. Then make measurements at one-meter intervals, for example, 1m, 2m, 3m, 4m, etc. The cord is marked with tape at these intervals. Be careful to not let probe hit the bottom sediments.)
  6. Check to see that the meter is in “dissolved oxygen % air saturation” mode (% saturation should be the default as you turn on the meter). If it is not in % saturation, press MODE until the units are in %.
  7. Allow temperature to stabilize (about 30 seconds).
  8. Record temperature on data sheet .
  9. Raise and lower the probe gently (about 2 inches per second) until % air saturation stabilizes. Record this percentage.
  10. Press MODE button once so dissolved oxygen is displayed in “mg/L”. Again raise and lower the probe until stable. Record this value.
  11. Lower probe to next depth.
  12. Press the MODE button to return to “% air saturation” mode. Repeat steps 5-9 as necessary.
  13. When finished, rinse probe with distilled water from the squirt bottle. Place probe in storage chamber and be sure the sponge inside is moistened. Turn off meter.
  14. Submit your data

* Never hold the meter over the water. Keep it securely inside the boat.
Put only the probe over and into the water.*