Hayward AquaRite 900 "High Salt" Light: What To Do When Salt Is Too High

What the "High Salt" Light Actually Means

The AquaRite 900 is tuned for a narrow salinity range. If the cell sees conductivity higher than expected, it interprets that as too much salt. To protect the cell and other equipment, the controller turns on the High Salt LED and can stop energizing the cell entirely.

High salt can also stress heaters and other metal components in the system. The water chemistry guidance is written to balance sanitation, comfort, and equipment life, so you want to bring salt back into that window.

Step-by-Step Troubleshooting

Owner-Level Checks

Confirm the reading with a test

1. Use a reliable salt test kit or meter.
2. Compare test results to the AquaRite salt display.
3. If the test shows salt comfortably in range, suspect a configuration or cell issue instead of immediately draining.

Review recent salt additions

1. Think through how much salt was added over the last few visits.
2. Verify the pool volume you used in your calculations. Underestimating volume is a common way to overshoot.

Determine target salinity

Use the recommended salt band and choose a target near the center. That gives you headroom for rain and refills.

Plan a partial drain and refill if truly high

1. Calculate the percentage of water to replace to drop from current salinity to target.
2. Drain to a safe level based on local rules and the pool structure. Never fully drain a vinyl pool and be careful with high groundwater.
3. Refill with fresh water, run the pump for several hours, then retest salt.

Tech-Level Checks

If tests do not support the High Salt warning:

Verify Turbo Cell type

As with low salt, a mismatched t code can warp the controller's salt calculations. Confirm the t setting matches the installed cell.

Check for scaling and cell issues

1. Remove and inspect the cell for heavy scale.
2. Clean as needed following the manual's acid wash procedure, then reinstall and retest.
3. A heavily scaled cell can behave unpredictably.

Use instant salinity and update average

1. Use the diagnostic button to view instant salinity.
2. If instant and test kit readings agree and only the average is high, use the update procedure to sync the average to the instant value.

Confirm there are no stray connections

Ensure there are no incorrect bonding or wiring practices tying the cell into other electrical equipment in ways that would affect the reading.

Common Parts That Fix This Problem

• There is no "High Salt part." The fix is usually water replacement.
• In some cases a new cell or board is needed if the reading remains obviously wrong after tests and cleaning.

Model-Specific Notes

• Larger cell models paired with smaller pools are more sensitive to high salt. Always respect the pool volume guidelines for the AQR925 and AQR940.
• Always check salt professionally before making large corrections. This is good practice in commercial settings.

How to Prevent High Salt Issues

• Log every bag of salt that goes into the pool and keep a running total.
• Never add salt "by feel." Always calculate and test first.
• Retest salt after rainy seasons or after large drains so you know where you stand.