4. If you continue to get error messages during calibration, clean the sensor.
5. If you continue to get error messages during calibration, soak the sensor in 100 mg/L nitrate standard for
several hours or overnight.
6. If you suspect port contamination, follow the instructions in the Cleaning a Sensor Port section.
7. If you continue to have trouble calibrating the nitrate sensor, contact your local YSI Representative or a YSI
Authorized Service Center.
Cleaning and Reconditioning the Nitrate Sensor
The nitrate sensor uses a PVC membrane. As always, when handling a sensor, care should be taken to avoid
damaging the membrane. After extensive use the membranes may become coated with a deposit or scoured
with fine scratches which may cause a slow or reduced response (low slope) or unstable readings. Deposits may
be removed with a fine jet of deionized water or rinsing in alcohol followed by soaking in 100 mg/L nitrate
calibration standard.
The sensor may require soaking in the high nitrate calibration solution to recover its performance. Soak in 100
mg/L for several hours or overnight.
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