SEN0711 accuracy at low ammonia concentrations
Dylan.McLaughlin 2026-10-22 02:12:19 47 Views1 Replies The listed accuracy for the SEN0711 Industrial RS485 Water Quality Ammonia Nitrogen & pH Sensor is ±3% FS. On the 0–100 mg/L range, we read that as ±3 mg/L at any reading. To keep toxic free ammonia (NH₃) below about 0.05 mg/L, we need to measure total ammonia nitrogen accurately in roughly the 0.5–5 mg/L range. To that end, we have a few questions:
1. What is the sensor’s detection limit and its accuracy in the 0–5 mg/L range?
2. The calibration guide uses 10 and 100 mg/L standards. If we calibrate with lower standards (for example, 0.5 and 5 mg/L), does accuracy improve in that range?
3. Has anyone tested this sensor at low concentrations in aquaculture water?
Thanks for any help!
hi，
The only accuracy spec published is ±3% FS over 0–100 mg/L (so yes, that reads as ±3 mg/L across the range; resolution is 0.01 mg/L). On low-range calibration: the sensor supports multi-point calibration, and calibrating at 0.5/5 mg/L instead of 10/100 should improve the fit in that region in principle — but since ammonia-N electrodes respond slowly and drift more at low concentration, verify it empirically with prepared standards in real water samples before relying on it. The auto pH compensation helps with the free-NH3 vs total-NH3 split, but the sensor measures total ammonia nitrogen.
And there is an important point: Your measurement range only takes up a very small portion of this sensor. It is recommended that you first check if you need an industrial-grade sensor or another sensor that is more suitable for your measurement range. If you use SEN0711, then rely more on actual measurements.
Jason.Miao 