Proper calibration of a dissolved oxygen (DO) meter is essential for accurate measurements in water quality testing. Whether you’re testing in the lab or the field, regular calibration ensures reliability, especially before critical testing or after prolonged storage.

This guide walks you through the basic steps for calibrating most Hanna Instruments DO meters, such as the HI98193, using either air calibration or zero oxygen solution.

What You’ll Need

• Your Hanna DO meter (e.g., HI98193, HI9829, HI2040, etc.)
• DO probe (polarographic or galvanic, depending on model)
• DO calibration solutions:
  • Zero oxygen solution (HI7040L)
  • Air calibration (using water-saturated air)
• Clean distilled or deionized water
• Lint-free cloth or tissue

Step 1: Prepare the Probe

1. Inspect the membrane: Ensure the DO probe membrane is clean, intact, and properly filled with electrolyte.
2. Condition the probe: If the probe hasn’t been used in a while, immerse it in water for 10–15 minutes to polarize (especially for polarographic probes).
3. Connect the probe to your meter and allow it to stabilize.

Step 2: Choose Your Calibration Type

Option A: Air Calibration: This method uses water-saturated air (100% DO) and is ideal for regular calibration.

1. Moisten a sponge or tissue and place it inside the Hanna calibration chamber (or a sealed BOD bottle or calibration cap).
2. Place the DO probe inside the chamber without touching the wet sponge.
3. Close the chamber and allow the reading to stabilize.
4. On your Hanna meter, select the calibration mode and follow the on-screen prompts.
5. The meter will recognize the air-saturated environment as 100% DO (or ~8.26 mg/L at 25°C).
6. Once complete, confirm and save the calibration.

Tip: Avoid bubbling water or submerging the probe during air calibration.

Option B: Zero Oxygen Calibration (Recommended for Accuracy): Use this method to establish the zero point, especially if your measurements are in very low DO ranges.

1. Pour a small amount of HI7040L zero oxygen solution into a beaker.
2. Rinse the probe with distilled water and blot dry.
3. Submerge the probe in the solution, stir gently, and allow to stabilize.
4. Follow the meter’s prompt to recognize this as 0% DO or 0.00 mg/L.
5. Confirm and save the calibration.

Step 3: Verify Calibration

After calibration, measure a known DO standard or perform a reading in a well-aerated body of water to verify accuracy. Recalibrate if readings are off.

Whether you’re conducting fieldwork or lab tests, calibrating your Hanna DO meter correctly ensures trustworthy results. The process is simple and takes just a few minutes, especially with Hanna’s intuitive interface and quality calibration solutions like HI7040L.

For model-specific instructions, always refer to the user manual or visit Hanna Instruments’ Knowledgebase.