Inflow and outflow monitoring for fish farms and conservation hatcheries — continuous dissolved-oxygen, ammonia, temperature and turbidity logging that protects stock and evidences compliance.
The constraints that shape every design decision
DO crashes kill stock within hours; monitoring must be continuous, alarmed and trustworthy, not periodic.
Un-ionised ammonia toxicity tracks pH and temperature, so several parameters must be logged and interpreted together.
Outflow quality must be evidenced against consent limits to protect the receiving water and the licence.
Our response to the environment above
Drift-stable DO, ammonia, temperature and turbidity sensing on inflow and outflow with local logging and alarms.
Configurable alerts on DO and ammonia give operators time to act before a welfare or compliance event.
An auditable outflow dataset evidences discharge quality against consent for the regulator.
For a farm or hatchery the same dataset does two jobs: it warns operators before a dissolved-oxygen or ammonia event harms the stock, and it evidences outflow quality against discharge consent — so the station is sized for reliability and alarm integrity above all.
Accuracy, drift and maintenance intervals for continuous aquaculture monitoring.
Range 0–20 mg/L; accuracy ±0.1 mg/L or ±2 %; drift <1 % per year. Luminescent membrane unaffected by H2S or CO2. Replace cap every 12–18 months.
Range 0–100 mg/L NH3-N; accuracy ±5 % or ±0.5 mg/L. Requires monthly calibration in 10 mg/L and 1 mg/L standards. Replace membrane every 6 months.
Range 0–2,000 NTU; accuracy ±2 % or ±0.1 NTU. Clean optical window weekly; calibrate with 20 NTU formazin standard quarterly.
Range −5 to +50 °C; accuracy ±0.1 °C. No drift; verify annually against certified reference thermometer.
Campbell CR6 or equivalent: 16-bit resolution, SD-card backup, battery-backed clock. Stores 1-min averages for 90+ days at 4 parameters.
Iridium SBD or 4G LTE-M modem transmits hourly bursts. Data rate ~2 KB/hour; latency <15 min. Fallback to local SD card on link failure.
Configurable SMS and email alerts on DO <4 mg/L or NH3 >0.5 mg/L. Relay output drives aerator or pump starter directly.
Time-series visualisation, trend export (CSV), API access for SCADA integration. TLS-encrypted, role-based access control.
| Sensor | Calibration Interval | Standard | Maintenance Action |
|---|---|---|---|
| DO (optical) | Monthly | Air-saturation check; 0 % with Na2SO3 | Clean lens; inspect cap for biofouling |
| Ammonia ISE | Monthly | 1 mg/L and 10 mg/L NH3-N | Replace fill solution; check junction |
| Turbidity | Quarterly | 0, 20, 200 NTU formazin | Clean window; verify zero in DI water |
| pH | Monthly | pH 4.01, 7.00, 10.01 buffers | Replace junction; rehydrate reference |
| Conductivity | Quarterly | 1,413 µS/cm standard | Clean cell; verify cell constant |
Values derived from FAO Technical Papers, EU Directive 2006/113/EC and national aquaculture codes.
High-fidelity sensing for stock welfare and discharge compliance
Luminescent lifetime-based optical sensor. Range: 0–20 mg/L (0–200 % sat). Accuracy: ±0.1 mg/L or ±1 % reading. Detection limit: 0.05 mg/L. Drift: <1 % per year. Response T90: <30 s. Membrane-free design resists biofouling.
Ion-selective electrode (ISE) with automatic temperature compensation. Range: 0–100 mg/L N. Accuracy: ±2 % full scale. Detection limit: 0.02 mg/L N. Cross-sensitivity to K⁺: <1 %. Weekly slope check required.
ISO 7027 compliant infrared 90° nephelometer. Range: 0–4000 NTU. Accuracy: ±2 % or ±0.5 NTU whichever is greater. Detection limit: 0.1 NTU. Wiper or copper guard available for biofouling control.
Combined probe: temperature ±0.05 °C (−5 to +50 °C), pH 0–14 ±0.02. ATC via NIST-traceable thermistor. 3-point calibration (pH 4.01, 7.00, 10.01 at 25 °C). Electrode offset <±20 mV.
16-channel, 24-bit ADC, ±0.05 % accuracy. Sampling interval: 1 min (process) / 15 min (compliance). 8 GB SD storage. Inputs: SDI-12, RS-485, 4–20 mA. Alarm outputs: relay + SMS gateway.
Not sure which technology fits your application? Our process engineers will review your water quality data, flow rate, and treatment targets — then recommend the optimal solution.
Contact UsTypical consent thresholds and operational target ranges
| Parameter | Typical Consent Limit | Operational Alert | Critical Alarm |
|---|---|---|---|
| Dissolved Oxygen | >6 mg/L (cold water) | <5.5 mg/L | <4.0 mg/L |
| Un-ionised NH₃ | <0.025 mg/L NH₃-N | >0.015 mg/L | >0.025 mg/L |
| Total Ammonia-N | <1.0 mg/L N | >0.8 mg/L | >1.0 mg/L |
| Turbidity (outflow) | <10 NTU | >8 NTU | >15 NTU |
| Temperature | ±2 °C of ambient | >±1.5 °C deviation | >±3 °C deviation |
| pH | 6.5–9.0 | <6.8 or >8.5 | <6.5 or >9.0 |
Traceable calibration and known measurement uncertainty
2-point calibration (0 % and 100 % saturation) verified by Winkler titration quarterly. Sensor cap replaced annually or when drift >2 %.
3-point calibration (0.1, 1.0, 10 mg/L N) in ionic strength adjustment (ISA) buffer. Slope 54–60 mV/decade validated each run. Reference electrode filled monthly.
4-point calibration (0, 20, 100, 800 NTU) using StablCal standards. Drift >5 % triggers service call. Quarterly verification with secondary standard.
pH 4.01, 7.00, 10.01 buffers at 25 °C. Electrode slope >95 % and offset <±20 mV. Fortnightly check in process water.
Combined expanded uncertainty (k=2): DO ±0.15 mg/L; ammonia ±0.04 mg/L N; turbidity ±3 % of reading; pH ±0.05. Documented per sensor.
Quarterly split-sample analysis by UKAS-accredited laboratory. Relative bias <10 % triggers root-cause review and recalibration.
Real-time alarming and auditable compliance records
The full remote autonomous monitoring-station programme and all deployment environments.
Read MoreA companion deployment environment.
Read MoreA companion deployment environment.
Read MoreA companion deployment environment.
Read MoreReynolds & Bauhm designs autonomous monitoring stations engineered to the specific demands of the site — survivable, self-sufficient and calibrated for a defensible long-baseline record.
Our expertise spans multiple industries with sector-specific water treatment solutions.