The YEX-BGA-406-S Online Blue Green Algae Sensor from Yexsensor delivers precise, continuous monitoring of cyanobacteria (blue-green algae) concentrations in various aquatic environments. This advanced optical sensor leverages fluorescence technology to provide reliable data for early detection of harmful algal blooms (HABs), supporting effective water quality management in rivers, lakes, oceans, harbors, and aquaculture facilities.

Designed for durability and ease of integration, the sensor offers a measuring range of 0–300.0 Kcells/mL with high resolution and accuracy. It supports RS-485 (Modbus/RTU) communication and optional 4-20mA output, making it ideal for integration into existing SCADA, PLC, or IoT-based monitoring systems. With IP68 protection and robust construction using ABS and 316L stainless steel, the YEX-BGA-406-S ensures long-term performance even in challenging marine or freshwater conditions.

Advanced Fluorescence-Based Detection Technology

The YEX-BGA-406-S operates on the principle of spectral fluorescence specific to cyanobacteria. Cyanobacteria contain unique pigments, primarily phycocyanin, that exhibit distinct absorption and emission peaks in the light spectrum. The sensor emits monochromatic light at the absorption wavelength into the water body. Cyanobacteria cells absorb this energy and re-emit light at a longer emission wavelength. The intensity of the emitted fluorescence is directly proportional to the concentration of cyanobacteria present.

This optical method provides highly specific detection of blue-green algae, distinguishing it from other microalgae or total chlorophyll measurements. Unlike traditional laboratory analysis, which requires sample collection, transport, and delayed results, the YEX-BGA-406-S delivers real-time data with minimal maintenance. The sensor achieves a resolution of 0.1 Kcells/mL and accuracy of ±3% (plus ±0.3℃ for temperature compensation), ensuring dependable readings even in dynamic water conditions.

Two-point calibration (zero in distilled water and slope in standard solution) maintains measurement integrity over time. The system performs optimally in water with turbidity below 50 NTU, with recommendations for multiple monitoring points due to the uneven natural distribution of algae in water bodies.

YEX-BGA-406-S Online Blue Green Algae Sensor Key Technical Specifications

Comprehensive Application Scenarios

Effective water quality management requires proactive monitoring of cyanobacteria, which can rapidly form blooms under nutrient-rich, warm conditions. The YEX-BGA-406-S addresses this need across multiple sectors:

Environmental Monitoring in Rivers and Lakes

Cyanobacteria blooms in freshwater systems threaten ecosystems, drinking water sources, and recreational areas by producing toxins such as microcystins. Deploy the sensor at strategic points in rivers and lakes to track concentration changes in real time. Data integration with multi-parameter systems (including temperature, dissolved oxygen, and nutrients) enables predictive modeling of bloom risks, allowing authorities to issue timely warnings and implement mitigation measures like aeration or nutrient control.

Ocean Harbor and Marine Algae Monitoring

In coastal harbors and open ocean environments, the sensor monitors marine cyanobacteria and related red algae. Harmful blooms can disrupt shipping, fisheries, and tourism. The YEX-BGA-406-S helps port authorities and environmental agencies detect early signs of blooms, supporting compliance with water quality regulations and protecting sensitive marine habitats.

Mariculture and Aquaculture Operations

Red algae and cyanobacteria pose significant risks in shellfish and fish farming by depleting oxygen and releasing toxins. Installing the sensor in aquaculture ponds or cages provides continuous oversight, enabling operators to adjust feeding, water exchange, or harvest schedules. This reduces mortality rates, improves product quality, and minimizes economic losses.

Green Algae Cultivation Equipment

In controlled algae production for biofuels, food supplements, or wastewater treatment, precise concentration control is essential. The YEX-BGA-406-S integrates into cultivation systems to optimize growth conditions and harvest timing, enhancing yield and efficiency while preventing contamination by unwanted cyanobacteria strains.

Drinking Water Treatment Plants

Early detection of incoming cyanobacteria helps treatment facilities optimize coagulation, filtration, and disinfection processes. Real-time data prevents toxin breakthrough and reduces operational costs associated with reactive treatment adjustments.

Research and Scientific Studies

Universities and research institutions use the sensor for long-term ecological studies, bloom dynamics modeling, and climate change impact assessments on aquatic systems. The Modbus protocol facilitates seamless data logging and analysis.

In all scenarios, the sensor promotes a solution-oriented approach: shifting from reactive crisis management to data-driven prevention, ultimately safeguarding public health, ecosystems, and economic interests.

Installation and Electrical Connection

1. Installation

Installation distance requirement: keep more than 5cm with the side wall and 20cm or more with the bottom.

2. Electrical connection

The cable is 5-core twisted pair shielded wire, the wire sequence definition:

• Red cord — power cord（12V～24VDC）

• Black cord — ground cord（GND）

• Blue cord — 485A

• Green cord — 485B

• Yellow cord — Current output (if unused, suspended)

The wiring sequence should be carefully checked before power-on to avoid unnecessary losses caused by faulty wiring.

Wiring instructions: considering the cable long-term immersion in water (including sea water) or exposure to air, all wiring are required to do waterproof treatment, the user cable should have a certain degree of corrosion resistance.

Maintenance

1. Maintenance procedures and methods

1.1 Maintenance schedule

1.2 Maintenance methods

• Sensor outer surface: Clean the outer surface of the sensor with tap water. If there is still debris left, wipe it with a soft, damp cloth. For some stubborn dirt, add some household washing liquid to the tap water to clean it.

• Check the cable of the sensor: the cable should not be tightened during normal operation. Otherwise, the internal cable of the cable may be broken and the sensor may not work normally.

• Check whether the sensor's measurement window is dirty or not.

1.3 Cautions

The probe contains sensitive optical and electronic components. Make sure the probe is not subject to severe mechanical shock. There are no parts inside the probe that require user maintenance.

2. Sensor calibration

a) Zero calibration: Take a proper amount of distilled water in a large bucket and place the sensor vertically in the solution. The front end of the sensor is at least 20 cm away from the bottom of the beaker. After 3 to 5 minutes, the value is stabilized and the zero point is calibrated. The instructions refer to the appendix.

b) Slope calibration: Place the sensor probe in the standard solution. The front end of the sensor is at least 20cm away from the bottom of the beaker. After 3 to 5 minutes, the slope is calibrated after the value is stable. The instructions refer to the appendix.

3. Frequently asked questions

Quality and Service

1. Quality assurance

• The quality inspection department has standardized inspection procedures, advanced and perfect testing equipment and means, and strictly in accordance with the regulations, to do a 72-hour aging test and stability test on the product, and not to allow one unqualified product to leave the factory.

2. Accessories spare and parts

This product includes:

• 1 sensor

• 1 copy of the manual

• 1 certificate

• 1 Cable (5 m)

3. After-sales service commitment

The company provides local after-sales service within one year from the date of sale, but does not include damage caused by improper use. If repair or adjustment is required, please return it, but the shipping cost must be conceited. If damaged on the way, the company will repair the damage of the instrument for free.

Frequently Asked Questions (FAQ)

Q1. What is the difference between this blue green algae sensor and a chlorophyll sensor?

This sensor specifically targets cyanobacteria via phycocyanin fluorescence, while chlorophyll sensors measure total algae biomass. It provides more accurate cyanobacteria-specific data essential for harmful bloom detection.

Q2. Can the YEX-BGA-406-S be used in seawater or high-salinity environments?

Yes. The 316L stainless steel construction and IP68 rating make it suitable for marine applications, including harbors and mariculture, provided turbidity remains below 50 NTU.

Q3. How often should calibration be performed?

Calibration frequency depends on regulatory requirements and observed drift. Many users perform two-point calibration monthly or quarterly under stable conditions. Always clean the window before calibrating.

Q4. What causes unstable or drifting readings?

Common causes include fouling on the optical window, cable issues, or improper installation depth. Clean the sensor surface thoroughly and verify distances from walls and bottom.

Q5. Is the sensor compatible with my existing Modbus system?

Yes. It uses standard Modbus/RTU protocol over RS-485, allowing straightforward integration with most PLCs, data loggers, and SCADA systems.

Q6. How does turbidity affect measurements?

The sensor performs best when turbidity is less than 50 NTU. Higher levels may scatter light and interfere with fluorescence detection. Consider pairing with a turbidity sensor for data validation.

Q7. Can multiple sensors be networked together?

Absolutely. The RS-485 interface supports multi-drop networking, enabling simultaneous monitoring at different depths or locations with a single controller.

Q8. What maintenance is required for long-term submerged deployment?

Regular cleaning of the optical window is essential. Inspect cables for damage and ensure proper waterproofing. In high-biofouling environments, schedule more frequent maintenance or explore anti-fouling accessories.

Why Choose Yexsensor for Your Water Quality Monitoring Needs

The YEX-BGA-406-S represents a reliable, cost-effective solution for proactive cyanobacteria management. Its combination of advanced fluorescence technology, rugged design, and easy integration helps organizations across environmental, industrial, and agricultural sectors prevent bloom-related risks while optimizing operations.

By investing in real-time monitoring, you gain actionable insights that protect water resources, ensure regulatory compliance, and support sustainable practices. Contact the Yexsensor team today to discuss custom configurations, integration support, or pilot deployments tailored to your specific water monitoring challenges.

With the YEX-BGA-406-S, achieve peace of mind through precise, continuous blue-green algae detection—empowering smarter decisions for healthier aquatic environments.