NO3-100 Nitrate Ion-Selective Electrode

Overview

The NO3-100 is a precision ion-selective electrode specifically designed for measuring nitrate (NO3⁻) concentration in water. Nitrate is a critical parameter for agricultural nutrient management, aquaculture water quality, environmental monitoring, and drinking water safety. This sensor provides fast, accurate measurements essential for optimizing crop production, protecting aquatic life, and ensuring water quality compliance.

Key Features

• High Selectivity: Specifically designed for nitrate ion detection
• Wide Range: Measures from 0.6 to 62,000 mg/L (ppm)
• Digital Output: RS485 Modbus RTU for seamless integration with SCADA and IoT systems
• Fast Response: Results within 30 seconds
• Automatic Temperature Compensation: Integrated PT1000 sensor for accurate readings
• Direct Connection: Connect directly to computer or PLC without additional instrumentation
• High Protection: IP68 waterproof rating ensures reliable operation

Applications

• Hydroponic nutrient solution monitoring
• Greenhouse fertigation control
• Agricultural irrigation water testing
• Aquaculture water quality monitoring
• Drinking water compliance testing
• Wastewater treatment optimization
• Environmental water monitoring
• Groundwater contamination assessment
• Agricultural runoff tracking
• Fertilizer application optimization

Technical Specifications

The NO3-100 delivers precise nitrate measurements from 0.6 to 62,000 mg/L with automatic temperature compensation via the integrated PT1000 sensor. The ion-selective membrane provides exceptional selectivity for nitrate ions, making it ideal for monitoring in complex agricultural and environmental water matrices.

Understanding Nitrate in Water

Nitrate is the final oxidation product of nitrogen and plays multiple critical roles:

Agricultural Applications

• Plant Nutrition: Primary nitrogen source for crop growth
• Fertigation Control: Optimizing nutrient delivery in hydroponics and irrigation
• Fertilizer Management: Preventing over-application and waste
• Crop Quality: Maintaining optimal N levels for yield and quality

Water Quality

• Drinking Water: EPA limit is 10 mg/L (as N) or 44 mg/L (as NO3⁻)
• Health Impact: High levels can cause methemoglobinemia (blue baby syndrome)
• Environmental: Excess nitrate causes eutrophication in water bodies
• Groundwater: Indicator of agricultural or sewage contamination

Aquaculture

• Fish Health: High nitrate (> 50 mg/L) can stress fish
• Biofilter Performance: Monitoring nitrification efficiency
• Water Exchange: Determining water change requirements

Typical Nitrate Levels

• Unpolluted natural water: < 1 mg/L
• Agricultural runoff: 10-100 mg/L
• Drinking water limit: 10 mg/L (as N)
• Hydroponic solutions: 100-200 mg/L
• Greenhouse irrigation: 50-150 mg/L
• Aquaculture (safe): < 50 mg/L

Connectivity and Integration

The NO3-100 supports dual output for integration into agricultural, aquaculture, and environmental systems:

RS485 Modbus RTU:

• Connect to Agrinovo Omni Genesis or Exodus controllers for cloud-based nitrate monitoring
• Multi-drop bus networking (up to 32 sensors per bus)
• Standard Modbus registers for NO3⁻ concentration and temperature
• Compatible with SCADA, PLC, fertigation controllers, and RAS management systems

RS485 Modbus RTU Output:

• Direct connection to fertigation dosing controllers for nitrogen adjustment
• Scalable output range mapped to measurement range
• Ideal for closed-loop nitrate management in hydroponics and greenhouse systems

IoT Integration:

• Pair with Omni Genesis/Exodus for automated fertilizer dosing based on nitrate levels
• Set alerts for environmental discharge compliance
• Historical data logging for nutrient use efficiency tracking
• Monitor water exchange requirements in aquaculture based on nitrate accumulation

Installation and Maintenance

Positioning: In hydroponic systems, install in the nutrient reservoir return line for well-mixed readings. In aquaculture, install in the sump or after the biofilter. For environmental monitoring, install at representative sampling points in streams or groundwater wells.

Calibration: Two-point calibration using KNO3 or NaNO3 standard solutions. For agriculture, calibrate at 50 mg/L and 200 mg/L. For drinking water compliance, calibrate at 5 mg/L and 50 mg/L. Recalibrate every 2-4 weeks.

Chloride Interference: The NO3⁻ ISE has cross-sensitivity to chloride (Cl⁻). In high-chloride waters (brackish, seawater), apply chloride correction factors. For freshwater and hydroponic applications, this interference is typically negligible.