WHITELEG SHRIMP FARMING PROCESS IN LINED POND SYSTEM
VI. COMMON ISSUES DURING WHITELEG SHRIMP FARMING IN LINED PONDS

 

1. ENVIRONMENTAL ISSUES

1.1. LARGE pH FLUCTUATION (Morning – Afternoon > 0.5)

a) Causes

  • Algae photosynthesize strongly during the day and respire actively at night.

  • Lined ponds have limited biological buffering capacity.

  • Low alkalinity (< 80 mg/L).

  • Heavy rainfall alternating with intense sunlight.

b) Signs

  • Low pH in the morning, high in the afternoon.

  • Reduced feeding in early morning and late afternoon.

  • Frequent molting in the morning with delayed shell hardening.

  • Shrimp surfacing sporadically at night.

c) Common Occurrence

  • All farming stages.

  • Seasonal transition periods with frequent rain.

d) Consequences

  • Prolonged stress in shrimp.

  • Reduced immunity; increased risk of hepatopancreatic and intestinal diseases.

  • Gradual mortality and body deformities.

e) Treatment Methods

  • Reduce algal density and limit excess nutrients.

  • Stabilize alkalinity (maintain at 120–150 mg/L) using CaO lime or Dolomite (5–7 kg/1000 m³), applied at 9:00 AM.

  • Supplement minerals with ALK-BALANCE (5 kg/1000 m³) or ULTRA-GREEN (4 kg/1000 m³), applied at 9:00 AM.

  • Apply probiotics such as BACILLUS SUBTILIS 1090 (500 g/1000 m³) or RHODO BACCIL (5 L/1000 m³), applied at 9:00 AM.

  • Avoid strong water treatment in the late afternoon or evening.

 

1.2. HIGH pH (> 8.5)

a) Causes

  • Dense algal bloom.

  • Prolonged sunny conditions.

  • High alkalinity combined with high algal density.

b) Signs

  • Significant increase in afternoon pH.

  • Dark green or yellow-green water.

  • Reduced feeding in the afternoon.

c) Common Occurrence

  • All farming stages.

  • Peak dry season.

d) Consequences

  • Increased NH₃ toxicity.

  • Stress and reduced growth performance.

e) Treatment Methods

  • Gradually reduce algae (avoid shock treatment).

  • Enhance organic decomposition using RHODO BACCIL (10 L/1000 m³) at 10:00 PM.

  • Apply BACILLUS SUBTILIS 1090 (500 g/1000 m³) the following morning at 9:00 AM.

  • Partial water exchange (10–20%).

  • Increase aeration in the late afternoon.

 

1.3. LOW pH (< 7.5)

a) Causes

  • Prolonged heavy rainfall.

  • Low alkalinity.

  • Strong organic decomposition.

b) Signs

  • Low morning pH.

  • Weak feeding response.

  • Soft shells and delayed hardening after molting.

c) Common Occurrence

  • Rainy season.

  • All farming stages.

d) Consequences

  • Delayed shell hardening.

  • Reduced mineral absorption.

  • Gradual mortality and body deformities.

e) Treatment Methods

  • Apply CaO lime (10 kg/1000 m³) at 9:00 AM and 7:00 PM.

  • Gradually increase alkalinity using ALK-BALANCE (5 kg/1000 m³) or ULTRA-GREEN (4 kg/1000 m³).

  • Supplement Ca–Mg–K minerals using SEA-MINER (5 kg/1000 m³), applied at 9:00 AM.

  • Limit water exchange during sudden rainfall.

 

1.4. HIGH ALKALINITY (> 200 mg/L)

a) Causes

  • Excessive lime application.

  • High-alkalinity water source.

  • Limited water exchange.

b) Signs

  • pH difficult to reduce.

  • Algae hard to control.

  • Uneven molting.

c) Common Occurrence

  • Mid and late culture stages.

  • Ponds treated with lime multiple times.

d) Consequences

  • Molting difficulties and irregular molting.

  • Mineral imbalance.

e) Treatment Methods

  • Stop lime application.

  • Dilute alkalinity through partial water exchange.

  • Stabilize water using probiotics such as BACILLUS SUBTILIS 1090 (500 g/1000 m³) or RHODO BACCIL (5 L/1000 m³), applied at 9:00 AM.

 

1.5. LOW ALKALINITY (< 80 mg/L)

a) Causes

  • Prolonged rainfall.

  • Lack of periodic alkalinity supplementation.

b) Signs

  • Strong pH fluctuation.

  • Weak shrimp with reduced feeding.

  • Weak molting and delayed shell hardening.

c) Common Occurrence

  • Early and late culture stages.

  • Rainy season.

d) Consequences

  • Slow growth rate.

  • Increased susceptibility to environmental shock.

e) Treatment Methods

  • Gradually increase alkalinity using CaO lime or Dolomite (5–7 kg/1000 m³), applied at 9:00 AM and 7:00 PM.

  • Supplement minerals using ALK-BALANCE (5 kg/1000 m³) or ULTRA-GREEN (4 kg/1000 m³), applied at 9:00 AM.

  • Maintain stable microbial populations with BACILLUS SUBTILIS 1090 (500 g/1000 m³) or RHODO BACCIL (5 L/1000 m³).

 

1.6. TOXIC GAS ACCUMULATION (NH₃, NO₂, H₂S)

a) Causes

  • Excess feed and shrimp waste accumulation.

  • Dirty pond bottom, poor siphoning.

  • Weak bottom microbial system.

b) Signs

  • Shrimp surfacing at night.

  • Black gills, reddish body.

  • Rotten egg smell in water.

c) Common Occurrence

  • From 30 days of culture onwards.

  • High stocking density.

d) Consequences

  • Hepatopancreatic damage.

  • Gradual mortality.

e) Treatment Methods

  • Periodic bottom siphoning.

  • Increase nighttime aeration.

  • Apply probiotics such as BACILLUS SUBTILIS 1090 (500 g/1000 m³), RHODO BACCIL (5 L/1000 m³) at 9:00 AM, or SITTO EM (5 L/1000 m³) at 7:00 PM.

  • Partial water exchange to dilute toxic gases.

  • Use SITTO YUCCA (1 L/1000 m³) when toxic gas levels spike.

  • Reduce feeding when water quality deteriorates.

 

1.7. LOW MINERAL CONTENT (Ca, Mg, K)

a) Causes

  • Frequent water exchange.

  • Prolonged rainfall.

  • Lack of mineral supplementation.

b) Signs

  • Soft shells, body deformities.

  • Uneven molting.

  • Slow growth.

c) Common Occurrence

  • From 20 days of culture onwards.

  • Frequent molting periods.

d) Consequences

  • Low survival rate.

  • Increased FCR.

e) Treatment Methods

  • Supplement minerals and maintain appropriate Ca:Mg:K ratio (1:3:1) using SEA-MINER (5 kg/1000 m³), applied at 9:00 AM.

  • Combine with feed mineral supplementation using D-MAX SHRIMP (10 ml/kg feed), once daily.

  • Add vitamins and electrolytes using SITTO C-SPARK (5 g/kg feed) and SITTO MIX (5 g/kg feed), once daily.

 

1.8. HIGH ACID SULFATE & HEAVY METALS (Fe, Al, Mn…)

a) Causes

  • Acidic water source.

  • Overuse of chemicals during water treatment.

b) Signs

  • Yellowish-brown water with sedimentation.

  • Yellow gills and body.

  • Sudden feed reduction.

c) Common Occurrence

  • Throughout the culture period.

  • During prolonged water exchange.

  • After heavy rainfall.

d) Consequences

  • Gill damage.

  • Weak shrimp, increased disease susceptibility.

e) Treatment Methods

  • Proper sedimentation and filtration before water intake.

  • Use heavy metal precipitation agents such as SITTO THIO 5000 (2.5 L/1000 m³) or SITTO POND MAGIC (2 kg/1000 m³), applied at 9:00 AM.

  • Stabilize pH and alkalinity before stocking using SITTO TAKE OFF (0.5 L/1000 m³) and ULTRA-GREEN (2 kg/1000 m³).

 

2. ALGAE & MICROBIAL ISSUES

2.1. RAPID ALGAL BLOOM – ALGAL CRASH

a) Causes

  • Excess nutrients: leftover feed, shrimp waste, organic accumulation.

  • Prolonged intense sunlight.

  • High alkalinity and unstable pH.

  • Weak microbial system.

  • Overuse of disinfectants.

b) Signs

  • Water quickly turns dark green, brown or yellow-green.

  • High afternoon pH (>8.5).

  • Sudden water clarity after 1–2 days with fishy odor.

  • Low morning DO, shrimp surfacing at night.

c) Common Occurrence

  • Shrimp older than 45 days.

  • Peak hot season.

  • High stocking density.

d) Consequences

  • Severe nighttime oxygen depletion.

  • Increased toxic gases (NH₃, H₂S).

  • Stress, reduced feeding, hepatopancreatic dysfunction.

  • Higher risk of EMS and white feces syndrome.

e) Treatment Methods

  • Gradually reduce algae (avoid shock treatment).

  • Temporarily reduce feeding.

  • Increase nighttime aeration.

  • Apply RHODO BACCIL (10 L/1000 m³) at 10:00 PM and BACILLUS SUBTILIS 1090 (500 g/1000 m³) the following morning at 9:00 AM.

  • Partial water exchange (10–20%).

  • Increase bottom siphoning.

  • Avoid strong algicides.

 

2.2. CLEAR WATER – ALGAE LOSS

a) Causes

  • Nutrient depletion for algae.

  • Overuse of disinfectants/algaecides.

  • Frequent water exchange.

  • Insufficient microbial balance.

b) Signs

  • Extremely clear water with visible pond bottom.

  • Low and unstable pH.

  • Rapid day–night temperature fluctuation.

  • Inconsistent feeding.

c) Common Occurrence

  • Early culture stage (after water treatment).

  • After algal crash.

  • Prolonged rainy season.

d) Consequences

  • Lack of biological buffering capacity.

  • Increased stress and molting difficulty.

  • Pathogenic bacteria proliferation.

  • Higher risk of hepatopancreatic and intestinal diseases.

e) Treatment Methods

  • Establish stable water color gradually using SITTO AQUA TONE (250 g/1000 m³).

  • Supplement trace minerals for algae using SITTO MINER-MAX (5 kg/1000 m³).

  • Maintain alkalinity at 120–150 mg/L using ALK-BALANCE or ULTRA-GREEN.

  • Apply BACILLUS SUBTILIS 1090 (500 g/1000 m³).

  • Avoid excessive water exchange.

 

2.3. MICROBIAL IMBALANCE

a) Causes

  • Overuse of disinfectants.

  • Lack of periodic probiotic supplementation.

  • High organic load with weak microbial system.

  • Frequent water exchange.

b) Signs

  • “Dead water”: poor color, fishy odor.

  • Unstable algal growth.

  • Rapid toxic gas increase despite low feeding.

  • Increased risk of gut and hepatopancreatic diseases.

c) Common Occurrence

  • Mid and late culture stages.

  • After chemical treatments.

  • High stocking density.

d) Consequences

  • Difficult environmental control.

  • Continuous toxic gas accumulation.

  • Chronic disease outbreaks.

  • Increased treatment costs, reduced farming efficiency.

e) Treatment Methods

  • Limit disinfectant usage.

  • Periodically apply probiotics for water and bottom treatment such as BACILLUS SUBTILIS 1090 (500 g/1000 m³) at 9:00 AM and SITTO EM (5 L/1000 m³) at 7:00 PM.

  • Increase aeration for microbial activity.

  • Strict feed management.

  • Regular bottom siphoning.