How to Change the Electrolyte Solution in the Q46 and Q45 Dissolved Ozone Sensors

Dissolved ozone sensors, like the Q46 and Q45 models, require regular maintenance to maintain accuracy. One essential task is replacing the electrolyte solution in the membrane. Here, I’ll walk you through the step-by-step process, and you can also check out our video tutorial for a visual guide.

Step 1: Remove the Sensor from the Flow Cell

The Q46 and Q45 sensors are typically installed in a constant-head flow cell, ensuring stable readings. Start by:

1. Unplugging the Electrical Connector: Located at the back of the sensor.
2. Removing the Sensor: Pull it out gently, and the O-ring seal will release it smoothly.

With the sensor in hand, let’s move on.

Step 2: Replace the Membrane

To access the membrane and solution:

1. Unscrew the Ring and Remove the Membrane: Take off the ring, discard the old membrane, and empty any remaining electrolyte.
2. Prepare the New Membrane: Retrieve a new membrane from its container, removing the yellow protective paper.
3. Insert the New Membrane: Place the clear membrane inside the ring and secure it by threading the ring and cap back together until fingertight.

Step 3: Add Electrolyte Solution

With the new membrane in place:

1. Fill the Cap with Electrolyte Solution: Fill to the bottom of the threads.
2. Prepare the Sensor for Reassembly: Remove the small side screw for easier reattachment.

Step 4: Reassemble the Sensor and Cap

To ensure the sensor functions correctly:

1. Attach the Cap at a 45° Angle: Thread the sensor and cap together, allowing some electrolyte to spill out—this is normal.
2. Tighten Until Sensor Contacts the Membrane: Tighten until the sensor tip just touches the membrane.
3. Replace the Small Plastic Screw: Reinsert and gently tighten the screw.

Step 5: Reinstall the Sensor

Once assembled:

1. Reconnect to the Flow Cell: Press the sensor back into the O-ring seal.
2. Plug in the Electrical Connector: Reattach the connector.

Warm-Up and Calibration Tips

After changing the electrolyte solution, allow the sensor a few hours to warm up before calibration. Trying to calibrate during warm-up may result in shifting readings. In some setups, replacing the electrolyte solution and membrane alone restores calibration without adjustments.

For more technical details, see our pages on the Q45 Sensor and the Q46 Sensor.

Watch our video tutorial for a full demonstration!