The use of water quality sensors is central to modern intensive and intelligent aquaculture. They enable real-time, continuous monitoring of key water parameters, helping farmers promptly identify issues and take action, thereby effectively reducing risks and improving yield and profitability.
Below are the main types of water quality sensors commonly used in aquaculture, along with their characteristics and application scenarios.
I. Overview of Core Water Quality Sensors
| Sensor Name | Core Parameter Measured | Key Characteristics | Typical Application Scenarios |
|---|---|---|---|
| Dissolved Oxygen Sensor | Dissolved Oxygen (DO) Concentration | - The lifeline of aquaculture, most critical. - Requires frequent calibration and maintenance. - Two main types: Optical (no consumables, low maintenance) and Electrode/Membrane (traditional, requires membrane & electrolyte replacement). |
- 24/7 real-time monitoring to prevent fish surfacing and suffocation. - Linking to aerators for intelligent oxygenation, saving energy. - High-density ponds, Intensive Recirculating Aquaculture Systems (RAS). |
| pH Sensor | Acidity/Alkalinity (pH) | - Affects organism physiology and toxin conversion. - Value is stable but changes have long-term impacts. - Requires regular calibration. |
- Monitoring pH stability to avoid stress. - Crucial after lime application or during algal blooms. - All farming types, especially for pH-sensitive species like shrimp and crab during larval stages. |
| Temperature Sensor | Water Temperature | - Mature technology, low cost, high reliability. - Affects DO, metabolic rates, and bacterial activity. - Often a base component of multi-parameter probes. |
- Daily monitoring to guide feeding rates (less feed in low temp, more in high temp). - Preventing stress from large temperature fluctuations during seasonal changes. - All farming scenarios, especially in greenhouses and RAS. |
| Ammonia Sensor | Total Ammonia / Ionized Ammonia Concentration | - Core toxicity monitor, directly reflects pollution levels. - Higher technical threshold, relatively expensive. - Requires careful maintenance and calibration. |
- Early warning of water quality deterioration in high-density culture. - Evaluating the efficiency of biofilters (in RAS). - Shrimp farming, valuable fish culture, RAS. |
| Nitrite Sensor | Nitrite Concentration | - ”Amplifier” of ammonia toxicity, highly toxic. - Online monitoring provides early warning. - Also requires regular maintenance. |
- Used alongside ammonia sensors to diagnose nitrification system health. - Critical after water suddenly turns turbid or after water exchange. |
| Salinity/Conductivity Sensor | Salinity or Conductivity Value | - Reflects the total ion concentration in water. - Essential for brackish water and marine aquaculture. - Stable with low maintenance. |
- Preparing artificial seawater in hatcheries. - Monitoring sudden salinity changes from heavy rain or freshwater inflow. - Farming euryhaline species like Vannamei shrimp, sea bass, grouper. |
| Turbidity/Suspended Solids Sensor | Water Turbidity | - Visually reflects water fertility and suspended particle content. - Helps assess algae density and silt content. |
- Evaluating live feed abundance (moderate turbidity can be beneficial). - Monitoring impacts from stormwater runoff or bottom disturbance. - Guiding water exchange or use of flocculants. |
| ORP Sensor | Oxidation-Reduction Potential | - Reflects the water’s “self-purification capacity” and overall oxidative level. - A comprehensive indicator. |
- In RAS, to determine appropriate ozone dosing. - Assessing bottom sediment pollution; low values indicate anaerobic, decaying conditions. |
II. Detailed Explanation of Key Sensors
1. Dissolved Oxygen Sensor
- Characteristics:
- Optical Method: Current mainstream. Measures fluorescence lifetime to calculate DO; does not consume oxygen, requires no membrane or electrolyte, offers long maintenance cycles and good stability.
- Electrode Method (Polarographic/Galvanic): Traditional technology. Requires periodic replacement of the oxygen-permeable membrane and electrolyte; response may slow due to membrane fouling, but cost is relatively lower.
- Scenarios: Indispensable in all aquaculture. Especially during night and early morning when photosynthesis stops but respiration continues, DO drops to its lowest; sensors are vital for warning and activating aeration equipment.
2. pH Sensor
- Characteristics: Uses a glass electrode sensitive to hydrogen ions. The electrode bulb must be kept clean, and regular calibration with standard buffer solutions (typically two-point calibration) is necessary.
- Scenarios:
- Shrimp Farming: Large daily pH fluctuations (>0.5) can cause stress molting. High pH increases ammonia toxicity.
- Algae Management: Sustained high pH often indicates excessive algae growth (e.g., blooms), requiring intervention.
3. Ammonia & Nitrite Sensors
- Characteristics: Both are toxic by-products of nitrogenous waste breakdown. Online sensors typically use colorimetric methods or ion-selective electrodes. Colorimetry is more precise but may require periodic reagent replacement.
- Scenarios:
- Recirculating Aquaculture Systems (RAS): Core monitoring parameters for real-time assessment of biofilter nitrification efficiency.
- Peak Feeding Periods: Heavy feeding leads to rapid increases in ammonia and nitrite from waste; online monitoring provides instant data to guide feed reduction or water exchange.
4. Multi-Parameter Water Quality Monitoring Stations
In modern large-scale aquaculture, the sensors mentioned above are often integrated into a multi-parameter water quality probe or online monitoring station. These systems transmit data wirelessly via a controller to the cloud or a mobile app, enabling remote, real-time monitoring and intelligent control (e.g., automatic activation of aerators).
III. Application Scenario Summary
- Traditional Earthen Pond Culture:
- Core Sensors: Dissolved Oxygen, pH, Temperature.
- Role: Prevent catastrophic oxygen depletion (“fish kill”), guide daily management (feeding, water adjustment). The most basic and cost-effective configuration.
- High-Density Intensive Culture / (e.g., Canvas Tank Culture):
- Core Sensors: Dissolved Oxygen, Ammonia, Nitrite, pH, Temperature.
- Role: High stocking density makes water prone to rapid deterioration; requires close monitoring of toxin levels for immediate intervention.
- Recirculating Aquaculture Systems (RAS):
- Core Sensors: All of the above, including ORP and Turbidity.
- Role: The “eyes” of the system. Data from all sensors forms the basis for the closed-loop control system, automatically regulating biofilters, protein skimmers, ozone dosing, etc., to ensure stable operation.
- Hatcheries (Larval Rearing):
- Core Sensors: Temperature, Salinity, pH, Dissolved Oxygen.
- Role: Larvae are extremely sensitive to water quality fluctuations; requires maintaining a highly stable and optimal environment.
Selection and Usage Advice
- Reliability Over Price: Accurate water quality data is directly linked to success. Choose reputable brands with mature technology.
- Maintenance is Key: Even the best sensors require regular calibration and cleaning. A strict maintenance schedule is essential for data accuracy.
- Configure According to Need: Select the most necessary sensors based on your farming model, species, and density; there’s no need to pursue a full suite unnecessarily.
In summary, water quality sensors are the “underwater sentinels” for aquaculture practitioners. They translate invisible water quality changes into readable data, serving as vital tools for scientific farming, precise management, and controllable risk.
We can also provide a variety of solutions for
1. Handheld meter for multi-parameter water quality
2. Floating Buoy system for multi-parameter water quality
3. Automatic cleaning brush for multi-parameter water sensor
4. Complete set of servers and software wireless module, supports RS485 GPRS /4g/WIFI/LORA/LORAWAN
please contact Honde Technology Co., LTD.
Email: info@hondetech.com
Company website: www.hondetechco.com
Tel: +86-15210548582
Post time: Oct-14-2025