Water remains hard even though the Aquabion softener appears to regenerate normally (no error codes).

Safety first: Turn off power and close inlet/outlet valves before opening any part of the system.

• Confirm hardness: Use a reliable hardness test kit to measure raw and softened water. If both are similar, the resin is not exchanging ions effectively.
• Check regeneration settings: Verify Aquabion controller settings for hardness, capacity, and salt dosage. Adjust according to your water analysis and Aquabion specifications.
• Inspect brine system: Ensure the brine tank has adequate salt, the brine injector is clean, and the brine line is not blocked so that proper brine reaches the resin.
• Resin condition: If the system is older (10+ years) or exposed to high iron, the ion exchange resin may be permanently fouled. Resin cleaning with an iron-removal product may help, but often the best solution is to replace the resin media in the Aquabion resin tank.

Warning: Resin replacement involves depressurizing, disconnecting the tank, and safely disposing of old resin. If unsure, hire a professional.