How to calibrate the Redox probe

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Estimated reading time: 2 min

About Redox probe calibration

In order for your Redox probe to remain accurate, it must be calibrated on a regular basis. New Redox probes must always be calibrated before being put to use.

Probe maintenance and care

In order for the ProfiLux to give you the most accurate probe readings, proper calibration must be performed. Here are some general tips to go by:

  • Calibrate NEW probes before being put to use; pH, redox, conductivity
  • If you are going to calibrate a probe that is already in-use, make sure to first clean it with warm water or 50/50 mix of water and white vinegar to remove build-up
  • In-between calibration steps, rinse and wipe the probe to prevent any cross-contamination between fluids
  • ALWAYS make sure the probe tip is kept clean and free from any detritus or foreign material
  • Make sure NO microbubbles get caught on the tip of the probe
  • Calibrate every 1 – 3 months

Probe calibration terminology

Before calibrating your probe, we recommend you become familiar with the terminology used during the calibration process.

Calibration tolerance
Used for telling the ProfiLux how much of a measurement swing is allowed during calibration. The larger the number, the large the tolerated swing, at the cost of probe accuracy.

By default, and in most cases, a calibration tolerance of 2 can be used.
A tolerance of 2 or 3 can be used for probes less than a year old. Probes greater than one year old, can use a tolerance of 4 or 5.

Calibration value 2
The mV value of the calibration fluid that will be used

What you’ll need…

In order to proceed with Redox probe calibration, you will need the following:

220mV calibration fluid (PL-0072)
Null plug (PL-1212)
Null plug is required for calibration

The Redox probe calibration process requires you to use a special plug called, Null plug. This is the blank BNC connector plug that was included with the ProfiLux 4 / 4e product box and Redox expansion cards. Please have this plug on-hand because you will need it for the calibration steps.

This Null plug will connect to the Redox port on the ProfiLux.

Listen for the 3 beeps!

During calibration, the ProfiLux will give the probe 900s (15 minutes) for the ADC values to stabilize. For steps 7 and 8, when you hear 3 beeps, the calibration step is complete. The amount of time it will take to hear these beeps will depend on probe age and set Calibration Tolerance.

Redox probe calibration steps

  1. Press any of the arrow keys on the ProfiLux and select Sensor settings
  2. Select Redox 1 or desired Redox probe you want to calibrate
  3. Select Calibration
  4. Select (1) for Cali.tolerance if probe is brand new or less than one year old

5. Select 220mV for Calibration value 2

6. Disconnect the Redox probe from the ProfiLux and connect the Null plug to the Redox port. Press the (√) key to continue.

7. The ProfiLux will now begin the countdown. Leave the null plug connected. Wait for the 3 beeps before proceeding to the next step.

8. Disconnect the null plug, reconnect the Redox probe, then dip the probe in the 220mV fluid and press the (√) key. When you hear the 3 beeps, select YES to save calibration.

9. Wipe the probe and put it back into the aquarium

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