What is the ideal pH for tilapia and vannamei?
Every species has a pH sweet spot, but the number that kills is not the average — it is the daily swing. A pond that reads pH 7.5 at dawn and pH 9.2 at 3 PM is more dangerous than a pond that sits steady at 8.7 all day.
Tilapia: pH 6.5–9.0 (optimal 7.0–8.5). Vannamei shrimp: pH 7.5–8.5 (optimal 7.8–8.3). Keep the daily swing under 0.5. Buffer weakly-buffered ponds with agricultural lime (CaCO₃) to raise alkalinity above 100 mg/L.
Step-by-step
- 1
Test at 6 AM and 3 PM every day
Dawn is the daily low (respiration builds CO₂ overnight). Afternoon is the daily high (photosynthesis strips CO₂). The gap is your swing.
- 2
Measure total alkalinity monthly
Alkalinity above 100 mg/L as CaCO₃ buffers pH naturally. Below 80 mg/L, pH will swing 1.0+ per day — regardless of what you do.
- 3
Raise pH slowly with lime
Agricultural lime (CaCO₃): 200–500 kg/hectare. Hydrated lime (Ca(OH)₂): 50–100 kg/hectare — faster but riskier. Apply in the morning; never dump the whole dose at once.
- 4
Lower pH with gypsum, not acid
Agricultural gypsum (CaSO₄): 50–150 kg/hectare drops pH 0.3–0.7 without crashing alkalinity. Never use sulphuric or hydrochloric acid — pH can overshoot below 6 and kill everything.
- 5
Stabilise the bloom
Dense algal blooms cause 1.5+ pH swings. Secchi disc reading below 25 cm means the bloom is too thick — partial exchange or dose zeolite.
- 6
Dolomite for double duty
Dolomite (CaMg(CO₃)₂): 300 kg/hectare raises pH and adds magnesium, which vannamei need for moulting. Best 15 days before stocking PL.
When to call a technician
- pH below 6.5 or above 9.5 at any reading.
- Daily swing exceeding 1.0 unit for more than 3 consecutive days.
- Sudden shrimp moulting failures or soft-shell after a pH crash.
- Fish surfacing with red patches on gills or fins after a bloom crash.
How CAMARON handles this automatically
CAMARON's 7-parameter alert engine flags pH swings, not just absolute values. The species profile knows vannamei tolerate a narrower band than tilapia and adjusts thresholds automatically — no manual configuration.
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