Summary #

To ensure long-term measurement accuracy and protect the MUI sensor, regular visual inspections and basic maintenance of the ION Director and its components are required. This guide covers sensor handling, replacing the sensor, and maintaining the hardware.

Applies to #

• ION Director

Sensor Handling & Cleaning #

The MUI sensor is a high-precision laboratory instrument. Its membrane is highly sensitive to mechanical stress.

• No Mechanical Cleaning: Never wipe, scrub, brush, or touch the tip of the sensor. Mechanical contact will permanently damage the delicate membrane.
• Rinsing the Cell: Regular cleaning is usually not necessary. However, if you suspect debris or organic buildup in the measurement cell, simply use the “Prepare measurement cell” function in the GHL Connect App or GHL Control Center to flush the chamber with Reference A.

MUI Sensor Replacement #

The MUI sensor has a limited chemical lifespan (with a 3-month limited warranty) and will eventually need to be replaced when the Sensor Performance drops permanently despite troubleshooting.

• Removing the Old Sensor: When you unscrew and pull out the old sensor, a small amount (a few milliliters) of fluid will remain in the measurement cell. Simply hold a paper towel or a small cup under the opening to catch the liquid as you remove the sensor.
• Installing the New Sensor: Insert the new sensor completely until it hits the stop. Ensure the slot in the sensor tip is aligned vertically before tightening the screw connection (Rubber seal → Pressure ring → Pressing screw).
• Conditioning: Every new MUI sensor must be conditioned. Run the preparation function to fill the cell with Reference A and let the new sensor soak for 12 hours before performing the first measurement.

Storage & Lifespan #

The MUI sensor’s internal chemistry degrades over time, regardless of whether it is actively measuring or sitting on a shelf.

• • Recommended Frequency: For optimal sensor stability and maximum lifespan, daily measurement is strongly recommended. Regular fluid movement helps maintain the electrochemical equilibrium of the membrane.
  • Short-Term Pauses: If you choose to measure only every few days, ensure the measurement cell remains filled with fluid (the ION Director handles this automatically after a measurement). A dry sensor will quickly become permanently damaged.
  • Avoid Long-Term Storage: It is not recommended to purchase sensors far in advance or store them for extended periods. The limited warranty begins at the time of purchase, and the sensor’s chemistry degrades naturally even when not in use.
  • Sensor Lifespan: The MUI sensor is a consumable wear part with a minimum guaranteed lifespan of 90 days under normal operating conditions. Actual lifespan may vary depending on operating conditions and water quality.
  • Reference Fluid Planning: Each measurement consumes 44–46 ml of Reference A and 44–46 ml of Reference B. Monitor fill levels regularly and replace reference fluids before they run empty to avoid interrupted measurements.

Hardware Maintenance #

Sample Water Inline Filter #

The inline filter protects the measurement cell and the MUI sensor from detritus, algae, and suspended particles.

• Inspection: Check the filter regularly for visible dirt, discoloration, or a restricted flow rate. The replacement frequency depends entirely on your aquarium’s bioload and suspended particles.
• Placement: To extend the life of the filter and prevent it from clogging too quickly, ensure the sample water intake tube is placed in a clean, calm area of your sump, away from detritus accumulation or macroalgae.

Tubing and Seals #

Airtightness is the most critical factor for the ION Director’s accuracy.

• Flex-PVC Tubing: Periodically check the Flex-PVC lines for Reference A, Reference B, and the sample water. Ensure all tube connections are seated firmly and show no signs of micro-bubbles or leaks.
• Sensor Seal: Whenever the sensor is removed or replaced, inspect the rubber seal for any signs of cracking or hardening. A damaged seal will allow air into the cell and ruin the measurement.

Dosing Pump Maintenance #

The ION Director relies on the mechanical precision of the connected GHL Doser to deliver consistent fluid volumes.

• Inspection and Cleaning: Regularly check the dosing pump heads for signs of wear, or plastic abrasion (dust) inside the housing. Dirty or worn-out rollers can cause inconsistent rotation.
• Maintenance Schedule: Clean the pump rollers and the internal housing if you notice any debris. If a pump head shows significant mechanical play or fails to rotate smoothly, it should be replaced to maintain measurement accuracy.
• Detailed Guide: For comprehensive instructions on maintaining your GHL Doser, please refer to our main article on GHL Doser – Maintenance & SA/EXT Configuration.