ANB Sensors AQ2 5m/50m spare transducer

The transducer is the active part of the AQ2 sensor, the face that meets the water. It is abraded at intervals and lasts about 300,000 measurements. The sensor monitors its own condition and reports a health number that tells you when to abrade and when a new transducer is due.

Replacement is quick and done in the field: dry the sensor, remove the clip held by two screws, pull the old transducer out, put a little grease on the rim of the new one and push it home on its key. The maker's video shows the steps.

How long a transducer lasts depends on how often you measure. At continuous measurement it is about 220 days, at one reading every 15 minutes about 2.8 years and at one reading an hour more than 11 years. Lower salinity can shorten this and higher salinity extend it.