Crab ponds differ from fish or shrimp ponds: aquatic weeds both produce and consume oxygen. By day they oxygenate the water; at night the whole weed bed switches to respiration and DO falls fast and deep before dawn. General reference lines for river crab and crayfish: optimal ≥ 5 mg/L, caution ≤ 3 mg/L, danger < 2 mg/L.
1. Weeds consume oxygen at night. Heavy weed cover means higher nocturnal oxygen demand, and a deeper pre-dawn minimum than open water.
2. Moulting is the most vulnerable stage. Low oxygen sharply increases soft-shell mortality and failed moults — and moulting often happens at night.
3. Weed die-off and poor bottom conditions. In hot weather or with poor weed management, decaying weed consumes oxygen and creates bottom-layer hypoxia — surface readings can look acceptable while the bottom is already critical.
| Scale | Recommended setup | Notes |
|---|---|---|
| 1 crab pond | 1 × DO sensor (with auto-clean) + 1 × 4-channel controller | Weeds foul probes quickly; auto-cleaning matters more here |
| Multiple ponds / sites | Per-pond setup, one shared account | Central overview, alerts grouped per pond, historical curves |
| Moulting season | Raise the caution threshold | Keep a wider safety margin during moulting |
Sensor placement must avoid dense weed beds and aerator jets — confirmed during survey.
Control logic sits on the pond-side controller. With 4G down it still switches aerators against the DO threshold and back-fills data on reconnection; the app shows whether you are on cloud control or running locally.
Crab ponds are usually remote and connectivity is unreliable by nature — this is what decides whether the system can be trusted.
1. Survey ponds, weed conditions, aerators and power · 2. Pilot one pond · 3. Verify over one production cycle · 4. Scale once confirmed.
That is exactly why auto-cleaning is included. A motorised wiper clears the sensing surface on a set interval, reducing manual diving maintenance.
Q: Should thresholds change during moulting?We recommend raising the caution line to keep a wider margin; exact values are set per pond.
Q: How many ponds can be managed?Multiple ponds grouped under one account, with the limit depending on the service tier.
Tell us your pond count, aerator count and current monitoring setup. We reply within 1 business day with equipment sizing and an indicative budget.
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