Replacement membranes, electrode tips and stirrer components for HORIBA dissolved oxygen electrodes. These are the wear parts of a membrane DO sensor and are expected to be replaced periodically — they are the difference between a DO electrode that holds calibration and one that appears to have failed.

Select the item for your electrode

• 5402 replacement DO membrane (3200781553) — for the #9552 series field DO electrodes, including 9552-20D and 9552-50D.
• 5401 replacement DO tip (3014072770) — for the #9550 and #9551 DO electrodes.
• 7544 replacement DO membrane (3200891724) — for the 9521-10D laboratory DO and BOD electrode.
• 7544 DO tip stirring set (3200897227) — replacement stirrer for the electrode tip of the 9521-10D DO electrode.

Check your electrode model before ordering — membranes are not interchangeable between the field 9552 series and the laboratory 9521-10D.

When to replace

Replace the membrane if the electrode is slow to reach a stable reading, will not hold calibration between uses, reads erratically, or if the membrane is visibly wrinkled, stretched, fouled, or has trapped bubbles or deposits beneath it. Membrane life depends on how dirty your samples are, so heavy wastewater and sludge users should expect to replace more often than laboratory users. Replacing a membrane is far cheaper than replacing an electrode, and most electrodes assumed to be dead simply need this service.

Good practice

• Keep at least one spare membrane on hand before a sampling event — a failed membrane in the field ends the day's DO data
• Always recalibrate after fitting a new membrane and electrolyte
• Avoid touching the membrane surface; handle by the cap
• Check for trapped air bubbles when fitting, since a bubble under the membrane will cause a false high reading

Documentation

• HORIBA water quality document library — electrode manuals and maintenance instructions

Related items

Complete replacement DO electrodes, calibration solutions and other electrode consumables are in the Horiba Parts & Accessories collection.

Browse all HORIBA instruments.