Cause: Air or contaminants at sample intake

Air or contaminants are being aspirated at the point where the sample water is drawn from the aquarium or sump.

Solution

Select another, calmer location in your sump to draw the sample water (away from skimmers or high-flow areas). Also, check the inline filter on the sample line; if it is clogged or dirty, replace it immediately to ensure unrestricted flow.

Cause: Micro-bubbles in supply lines

Small air bubbles are trapped in the reference or sample tubes, preventing the sensor from getting a stable reading.

Solution

Check all tube connectors for air tightness. Ensure that the Reference A and B bottles still contain enough fluid and that the internal tubes reach the bottom. Use Prime measurement cell until the lines are completely free of visible bubbles.

Cause: Improper tubing material

Using silicone tubes allows air to diffuse through the walls over time, leading to constant micro-bubble formation.

Solution

The complete path for the sample water and References A and B must be made of Flex-PVC tubing (before and after the pumps). Replace any silicone tubing in these sections to ensure an airtight system.

Cause: Sensor screw connection leaking

If the sensor screw connection is loose or assembled incorrectly, air enters the measurement cell directly at the sensor head.

Solution

Verify the assembly order: Rubber seal → Pressure ring → Pressing screw. Inspect the rubber for cracks. Tighten the screw sufficiently and consider coating the sensor shaft lightly with Vaseline to improve the seal.

Cause: Tubing length on inlet side

Longer tubing increases the likelihood of air pockets forming, especially during long measurement pauses.

Solution

Keep all inlet tubes (from the tank/bottles to the Doser) as short as practically possible.

Cause: Depleted MUI sensor

The sensor has reached the end of its chemical lifespan

Solution

If all physical causes (air, tubes, seals) are ruled out, replace the MUI sensor. Remember the initial 12-hour conditioning in Reference A for the new sensor.

Cause: Electromagnetic Interference (EMI)

High-voltage cables near the sensor cable are distorting the signal.

Solution

Route the PS/2 sensor cable away from power cords for large pumps, heaters, or LED ballasts. Ensure the plug is fully inserted into the back of the ION Director.

Cause: Poorly calibrated or malfunctioning dosing pumps

The ION Director requires consistent fluid delivery for its calculations. Inaccurate calibration, blocked pump rollers, or a worn-out pump head will lead to measurement drift or jumping values.

Solution

1. Verify Pump Calibration: Ensure all three pumps (Sample, Ref A, Ref B) are reasonably calibrated using a graduated cylinder. If the delivered volumes are inconsistent, perform a fresh calibration.
2. Check for Blockages: Ensure the pump rollers spin freely and are not stuck due to salt creep or debris. Use the “Manual Dosing” buttons to test each pump individually and verify that fluid is moving through the lines.
3. Inspect Pump Heads: Check the tubing and rollers inside the dosing pump heads for kinks or flattened sections. Replace these parts if necessary.

Cause: Incorrect sensor alignment

The sensor is not seated correctly, or the tip is oriented in a way that traps air or disrupts flow.

Solution

Push the sensor into the cell until it hits the stop. Crucially, the slot in the sensor tip must be aligned vertically to ensure proper fluid contact and air evacuation.

Cause: Initial sensor conditioning skipped or incomplete

A newly installed MUI sensor that has not completed its full initial conditioning period will produce inaccurate or implausible readings on its first measurements.

Solution

Ensure the sensor was conditioned in Reference A for at least 12 hours after installation, using the “Prepare measurement cell” function, before running the first measurement. If in doubt, repeat the conditioning step before troubleshooting further.

Cause: Insufficient resting time between actions

Starting a measurement too soon after any action (e.g., measurement, priming measurement cell, or a device restart) disrupts the sensor’s electrochemical equilibrium.

Solution

A one-hour wait time must be observed after any action, or device restart before starting a new measurement to ensure sensor stability.

Cause: Reference fluid contamination or evaporation

Contamination (e.g., algae growth) or evaporation can change the concentration of the reference fluids, leading to inaccurate readings.

Solution

Ensure that the special caps are used on the reference bottles to prevent evaporation. Keep the fluids clean and free of debris. If you notice algae or cloudiness in the bottles, replace the fluid immediately.

Cause: Comparison with manual test kits

Manual tests are subject to lighting conditions, reagent age, and subjective color interpretation.

Solution

Trust the ION Director’s trend over single manual measurements. If you have more confidence in a professional ICP laboratory analysis, you can apply a constant deviation as an Offset in the ION Director settings.

Cause: Electromagnetic Interference (EMI)

High-voltage cables near the sensor cable are distorting the signal.

Solution

Route the PS/2 sensor cable away from power cords for large pumps, heaters, or LED ballasts. Ensure the plug is fully inserted into the back of the ION Director.

Cause: PAB communication or assignment issues

The ION Director cannot trigger its pumps if the Doser is not correctly assigned or the PAB cable is loose.

Solution

Verify PAB assignment in GHL Connect app or GHL Control Center. Check that the PAB cables are firmly plugged in and that the Doser’s status LEDs indicate a normal state.

Cause: Low reference fluid levels

If the controller detects that the calculated fluid level for the references is too low, it will prevent a measurement from starting to avoid drawing air into the measurement cell.

Solution

Check the fluid levels in the GHL Connect app or GHL Control Center. After refilling or replacing the reference bottles, you must manually refill the fluid level in the software to enable the measurement function again.

Cause: No Doser assigned via PAB (for ProfiLux Controllers only)

The ION Director does not have its own internal pumps and relies entirely on a GHL Doser for fluid delivery. If no Doser is assigned via PAB, the system cannot initiate a measurement.

Solution

Ensure that a GHL Doser is correctly connected via PAB and assigned in the system configuration. Without a valid PAB assignment, the ION Director lacks the hardware (pumps) necessary to perform a measurement cycle.

Cause: Comparison with manual test kits or ICP

Manual test kits and ICP laboratory results are not a reliable benchmark for the ION Director’s lab-grade accuracy. Manual tests are prone to subjective color interpretation, lighting conditions, and reagent age, while ICP results can vary between laboratories due to differing maintenance standards and margins of error. The ION Director’s sensor itself operates within a tolerance of ±2% or ±2ppm (whichever is greater), which is already tighter than either comparison method can reliably resolve.

Solution

Trust the ION Director’s trend over single manual or ICP measurements. To verify absolute accuracy, always perform a reference test using the GHL Multi-Reference solution.

Performing a Reference Test with the Multi-Reference Solution

The GHL Multi-Reference solution provides fixed, lab-verified values (accurate to within ±1%) for all five parameters and is the most reliable way to verify and fine-tune the ION Director’s accuracy.

Procedure:

1. Remove the Sample water tube from the aquarium/sump.
2. Run the Sample water pump manually until the tube is empty up to the ION Director inlet.
3. Wipe the end of the tube dry and insert it into the Multi-Reference bottle.
4. Run the Sample water pump manually until the tube is filled up to the ION Director inlet.
5. In the ION Director settings, press Prepare measurement cell.
6. Wait at least one hour to allow the sensor to reach electrochemical equilibrium.
7. Press Start measurement now.
8. Compare the results to the fixed values printed on the bottle. Accounting for all tolerances, a total deviation of up to ±3% or ±3ppm (whichever is greater) can be expected.

After testing:

1. Remove the sample tube from the bottle.
2. Run the Sample water pump manually until the tube is empty up to the ION Director inlet.
3. Wipe the tube dry and reinsert it into the aquarium/sump.
4. Run the Sample water pump manually until the tube is filled up to the ION Director inlet.
5. Press Prepare measurement cell again.
6. The ION Director can now resume normal operation according to its measurement schedule.