HUSBANDRY · CONTROLLED DOCUMENT
AE-SOP-0118 — Overnight Anomaly Sweep
To run an automated dawn analysis of every overnight sensor series, detecting pH crashes, temperature excursions, stuck or stale probes, and slow parameter drift before staff arrive. The sweep is zone-aware so expected CO₂-coupled movement in planted systems is not mistaken for a crash, guaranteeing that the morning issue register reflects real failures and not noise.
ActiveHusbandryRev B
1. Purpose
To run an automated dawn analysis of every overnight sensor series, detecting pH crashes, temperature excursions, stuck or stale probes, and slow parameter drift before staff arrive. The sweep is zone-aware so expected CO₂-coupled movement in planted systems is not mistaken for a crash, guaranteeing that the morning issue register reflects real failures and not noise.
2. Scope
All station zones; the sweep runs at 06:00 local each day.
- In scope: Overnight time-series analysis, false-positive suppression, cross-node validation, and staging of findings for human triage.
- Out of scope: Live emergency response to a detected failure, which follows AE-SOP-0211; the exchange decisions themselves, which follow AE-SOP-0112.
3. Definitions
| Term | Definition |
|---|---|
| Overnight Series | The continuous sensor record for each channel from last-staff-out to the 06:00 sweep. |
| CO₂ Coupling | The expected nightly pH decline in planted zones as photosynthesis stops; excluded from crash logic. |
| Stale Probe | A sensor returning an unchanging or frozen value, treated as a failure until proven otherwise. |
| Cross-Validation | Confirming a flagged reading against neighbouring mesh nodes before raising it. |
4. Responsibilities
| Role | Responsibility |
|---|---|
| NEREID Liaison (Owner) | Owns the sweep logic; tunes zone exclusions and reviews staged findings each morning. |
| Husbandry Triage Staff | Works the staged findings into the issue register and dispatches response. |
| Engineering Dept. | Investigates flagged probe and equipment faults raised by the sweep. |
| NEREID | Runs the 06:00 analysis, suppresses expected movement, cross-validates, and stages — never auto-edits the register. |
5. Anomaly Detection Tiers
| Anomaly | Detection Threshold | Severity | Action |
|---|---|---|---|
| Temperature excursion | > 1.0 °C from setpoint | Critical | Page on-call immediately |
| pH crash (non-planted) | Drop > 0.3 in < 2 h | Critical | Page on-call immediately |
| Stuck / stale probe | No change > 90 min | High | Stage + flag Engineering |
| Slow parameter drift | Trend beyond band over night | Routine | Stage for morning triage |
Note. Temperature excursions and stuck probes are surfaced first — they kill fastest and a frozen probe can mask a real failure.
6. Materials & Equipment
- Full AquaLink mesh time-series feed
- Zone metadata for CO₂-coupling exclusions
- Neighbour-node topology map for cross-validation
- Ops log and issue register (read-staging access only)
- On-call paging integration
- Probe calibration and age records
7. Procedure
7.1 Acquisition
- Pull the overnight series for every channel at 06:00 local.
- Load zone metadata to identify planted, CO₂-coupled systems.
- Identify the expected nightly pH envelope per zone.
7.2 Analysis
- Exclude expected CO₂-coupled pH movement in planted zones from crash logic.
- Flag temperature excursions and stuck or stale probes first.
- Detect slow drift beyond band across the night.
- Cross-validate each flag against neighbouring nodes before raising it.
7.3 Staging
- Page on-call directly for Critical-severity findings.
- Stage all findings to the ops log for human triage.
- Never auto-edit the issue register — staging only.
8. Records
- Daily sweep report with all flags and severities (retained 1 year)
- Cross-validation results per flag
- Critical-page event log
- Suppressed-movement log for planted zones
- Probe fault referrals to Engineering
9. References
- AE-SOP-0112 — Dynamic Water-Change Protocol
- AE-SOP-0211 — Cold-Water Life-Support Failure Response
- AE-MET-027 — Station Dissolved Oxygen
- AE-MET-036 — Sensor Mesh Coverage
10. Revision History
| Rev | Date | Author | Summary |
|---|---|---|---|
| A | 2089-04-11 | NEREID Liaison | Initial issue; basic crash and excursion detection at dawn. |
| B | 2090-03-04 | NEREID Liaison | Added zone-aware CO₂ suppression, stale-probe logic, and neighbour cross-validation. |