How do I prevent algae bloom in aquaculture ponds?
A healthy algal bloom feeds the food web, generates daytime oxygen, and shades the pond bottom. A runaway bloom crashes DO overnight, releases stored ammonia when it dies, and cracks pH. The line between good and dangerous is a Secchi disc reading.
Keep Secchi visibility between 30 and 45 cm. Cut fertiliser and feed by 30% if it drops below 25 cm. Use zeolite (100 kg/hectare) or a partial water exchange to thin an over-dense bloom. Never let a bloom crash without aerators running 24/7.
Step-by-step
- 1
Daily Secchi disc reading
Lower the disc until it disappears. Above 45 cm: bloom too thin — fertilise. 30–45 cm: healthy. 25–30 cm: warning zone. Below 25 cm: intervene.
- 2
Reduce phosphorus inputs
Uneaten feed and organic fertilisers drive blooms. Cut ration by 20–30% and stop dosing DAP or urea until Secchi returns to 30+.
- 3
Zeolite 100 kg/hectare
Adsorbs ammonium (the nitrogen source blooms feed on) and settles suspended cells. Broadcast in shallow zones on a bright morning.
- 4
Partial water exchange 15–20%
Drain surface water where blooms concentrate. Refill from a bloom-free source at night to minimise thermal shock.
- 5
Copper sulphate 0.3–0.5 ppm (advanced)
For blue-green (cyanobacteria) blooms only. Requires alkalinity above 100 mg/L to buffer the pH drop. Never in ponds with newly-stocked PL.
- 6
Aerators on 24/7 during and after a crash
When a dense bloom dies suddenly, DO can drop 4 mg/L in 6 hours. Keep every aerator running until Secchi and DO stabilise for 48 hours.
When to call a technician
- Pond turns from green to brown-red or milky-white within 24 hours (algal die-off).
- Foul smell (rotten-egg H₂S) rising from the pond bottom.
- Fish or shrimp mortality within 6 hours of a bloom crash.
- Persistent cyanobacterial (blue-green) bloom with surface scum.
How CAMARON handles this automatically
CAMARON's satellite remote-sensing overlay flags NDVI spikes and algal-bloom risk from Sentinel Hub weekly, and the daily Secchi entry auto-scores your bloom health 0–100. When the score drops below 40, an alert routes to your feed advisor.
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