Water quality is one of the most important factors in shrimp farming. A pond may look normal from the outside, but changes in water parameters can affect shrimp health and farm performance.
Among the major water-quality parameters, pH is particularly important because it influences the chemical conditions of the pond and can affect how shrimp respond to their environment.
For shrimp farmers, the concern is not simply whether pH is high or low. Sudden changes and prolonged conditions outside the suitable range can create stress and disturb the balance of the pond.
So, what happens when pH falls? And what happens when it rises?
What Happens When pH Falls?
When pond pH drops below the suitable range, shrimp can experience increased environmental stress.
A decline in pH can occur because of factors such as rainfall, changes in carbon dioxide levels, decomposition of organic matter and other changes in pond conditions.
When the change is significant or happens suddenly, shrimp may become stressed and their normal behaviour can be affected.
Feeding Can Be Affected
One of the things farmers may notice during poor pond conditions is a change in feeding behaviour.
Stressed shrimp may reduce their feed intake. If farmers continue feeding at the same level without considering what is happening in the pond, uneaten feed can remain in the water.
This can contribute to increasing organic matter and place additional pressure on water quality.
That is why changes in feeding behaviour should not always be looked at separately. Water-quality conditions, including pH, should also be checked.
Low pH Can Disturb Pond Conditions
pH is connected to the overall chemical environment of the pond. When it moves significantly away from the suitable range, other water-quality processes can also be affected.
This is particularly important in intensive shrimp farming, where several factors interact continuously.
Rather than reacting only after shrimp show visible stress, farmers can use regular pH measurements to identify changes earlier and understand whether the pond is moving away from its normal condition.
What Happens When pH Rises?
High pH can create a different set of concerns.
Pond pH naturally changes during the day, and higher readings can occur during periods of strong photosynthetic activity. However, excessively high pH or large daily fluctuations can create an unfavourable environment for shrimp.
Shrimp may experience stress when pH moves beyond the suitable range, particularly when the change is rapid.
High pH and Ammonia Toxicity
One of the most important reasons farmers need to pay attention to high pH is its relationship with ammonia.
Ammonia exists in different forms in water. As pH increases, the proportion of ammonia present in the more toxic un-ionised form also increases.
This means that the same total ammonia concentration can represent a greater risk at higher pH conditions.
Therefore, checking ammonia alone may not provide the complete picture. Farmers should understand pH alongside other important water-quality parameters.
High pH Can Affect Pond Balance
High pH can also indicate significant changes in the pond's biological activity.
For example, during the daytime, algae and other photosynthetic organisms consume carbon dioxide, which can cause pH to increase. If this daily rise becomes excessive, it can indicate that the pond is experiencing considerable fluctuations.
This is why looking at a single pH number is not always enough.
The trend matters.
Low pH vs High pH: What Should Farmers Watch?
Both directions can create problems when pH moves significantly outside the suitable range.
| Low pH | High pH |
| Can cause shrimp stress | Can cause shrimp stress |
| Feeding may reduce | Feeding behaviour may be affected |
| Can indicate changing pond conditions | Can indicate strong photosynthetic activity |
| May occur after rainfall or other changes | Can increase during daytime |
| Can disturb overall pond balance | Can increase ammonia toxicity risk |
The key point is that both low and high pH need attention. Farmers should not wait until shrimp show obvious problems before checking the pond.
What Is the Suitable pH Range for Shrimp Farming?
For the shrimp farming conditions discussed in this series, a commonly targeted pond pH range is around 7.5–8.5.
However, maintaining a suitable number is only one part of pH management. Farmers should also pay attention to stability and daily fluctuations.
A pond that repeatedly moves through large pH changes may require closer observation even if an individual reading appears acceptable.
This is why recording pH readings over time can be more useful than checking only when a problem appears.
Why Regular pH Testing Matters
A pond may look clear, green or otherwise normal while its pH is changing.
Visual observation alone cannot tell a farmer the exact pH of the water.
Regular testing provides an actual number that can be recorded and compared with previous readings. This helps farmers understand whether pH is stable, gradually changing or showing unusual fluctuations.
Testing is particularly useful after events such as heavy rainfall or other noticeable changes in pond conditions.
The goal is not simply to test when shrimp are already under stress. The goal is to know what is happening in the water before making important crop-management decisions.
Smart Farming Starts With Knowing Your Water
Shrimp farming involves constant decisions about feeding, water management and overall crop care.
Making those decisions based only on assumptions can create unnecessary risks. Regular water-quality testing gives farmers information they can use to understand their pond more accurately.
pH is one of the key numbers that should be part of this monitoring process.
When pH falls, understand why. When pH rises, understand why. And before reacting, test the water and know the actual condition of your pond.
Initiated by Tel-Aqua — Lab in Your Pocket.
