YSI EXO 2 Multiparameter Sonde
The EXO2 is a high-performance multiparameter water quality sonde designed for unattended, long-term environmental monitoring. Built for demanding deployments, the EXO2 combines rugged durability, advanced sensor technology, and powerful anti-fouling capabilities to deliver accurate, reliable data over extended periods.
With seven universal sensor ports, including a central anti-fouling wiper port, an optional depth sensor, and an integrated battery compartment, the EXO2 offers exceptional flexibility for complex water quality monitoring applications.
Please Note: Powered by 4 D-cell batteries. For an externally powered version without a battery compartment, see the EXO2s. This listing is for the instrument only. Cables, sensors, and accessories are sold separately.
Built for Reliable Long-Term Deployment
Engineered for harsh and remote environments, the EXO2 features corrosion-resistant titanium construction, pressure-rated housing to 250 metres, and fully sealed, laser-welded sensors for maximum durability and performance.
Its low power consumption, onboard memory, and integrated anti-fouling system allow autonomous deployments for over three months.
Key durability features include:
Corrosion-resistant titanium sensors and bulkhead
Fully sealed, laser-welded titanium sensors and wiper
Wet-mate neoprene connectors for easy deployment
High-impact, temperature-resistant housing
Pressure-rated to 250 metres
Mechanically and electrically isolated internal components
Patented anti-fouling technology
Backed by a 3-year warranty
Advanced Anti-Fouling Performance
The EXO2’s high-torque central wiper with dense bristles actively cleans sensors during deployment, helping prevent fouling and maintaining data quality over long monitoring periods. This makes it particularly effective in challenging environments where biofouling can impact sensor performance.
Intuitive Operation & Seamless Integration
Designed for efficient setup and operation, the EXO2 features universal sensor ports, automatic sensor recognition, guided calibration workflows, and SmartQC™ quality assurance to simplify field preparation.
Users can access live data directly through the EXO Handheld or the Kor Mobile App, while seamless integration with remote telemetry systems enables real-time monitoring.
Comprehensive Water Quality Monitoring
The EXO2 supports an extensive range of water quality parameters, including:
Temperature
Conductivity / Specific Conductivity / NLF Conductivity
Salinity
Resistivity
Total Dissolved Solids (TDS)
Water Density
Dissolved Oxygen (DO)
Local DO
pH
ORP
Turbidity
Total Suspended Solids (TSS)
fDOM
Total Algae (Chlorophyll, Phycocyanin, Phycoerythrin)
ISE Ammonium / Ammonia / Chloride / Nitrate
UV Nitrate
Rhodamine WT
Photosynthetically Active Radiation (PAR)
Depth
Vertical Position
Absolute Pressure
Suitable Applications
The EXO2 is designed for a broad range of monitoring applications, including:
Surface water (rivers, lakes, streams)
Coastal, estuarine, and marine monitoring
Source and drinking water
Stormwater systems
Groundwater monitoring
Aquaculture
Wastewater treatment
Industrial and urban water systems
Other EXO Sonde Options
Explore the full EXO sonde range from YSI:
EXO1 – 4 sensor ports (also available without battery compartment as EXO1s)
EXO2 – 7 sensor ports with central wiper (also available as EXO2s)
EXO3 – 5 sensor ports with central wiper (also available as EXO3s)
Combining advanced anti-fouling protection, flexible sensor configuration, and long-term reliability, the EXO2 is an ideal solution for continuous water quality monitoring in challenging environments.
Depth Rating | 250 m (820 ft) | |
Materials | Xenoy®, Lexan®, titanium, 316 stainless steel | |
Internal Logging Memory Capacity | >1,000,000 logged readings, 512 MB memory | |
Software | Kor Software | |
Application | Kor Desktop, Kor Mobile | |
Power Requirements | Internal: 9 - 16 VDC External: (4) D-cell alkaline batteries | |
Battery Life | 90 days* | |
Communications | Sonde: Bluetooth (Wireless); RS-485 (Field Cable) | |
Operating Temperature | -5 to 50°C (23 to 122°F) | |
Storage Temperature | -20 to 80°C (-4 to 176°F) | |
Diameter | 7.62 cm (3.00 in) | |
Length | 70.52 cm (27.76 in) | |
Weight | 3.60 kg (7.94 lbs) | |
Peripheral Ports | 1 power communication port; 1 auxiliary port for third-party sensors (future functionality; not active yet) | |
Sample Rate | Up to 4 Hz | |
Sensor Ports | 7 (6 ports available when central wiper used) | |
Anti-Fouling | With a central wiper occupying a sensor port | |
Waterproof | Yes | |
User Calibration | Yes | |
Languages | English, Spanish, French, Japanese, German, Chinese | |
Warranty: 3 yrs | Sonde; handheld | |
Warranty: 2 yrs | Cables; conductivity/temperature and optical sensors; electronics base for pH, pH/ORP, ammonium, chloride, and nitrate sensors | |
Warranty: 1 yr | Optical DO cap and replaceable reagent modules for pH and pH/ORP sensors | |
Warranty: 3 mos | Replaceable reagent modules for ammonium, chloride, and nitrate sensors | |
*Typically 90 days at 20˚C at a 15-minute logging interval; temperature/conductivity, pH/ORP, DO, total algae, and turbidity sensors installed with a central wiper that rotates once per logging interval on EXO2. Battery life is heavily dependent on sensor configuration.
Ammonium | Ammonium Sensor | 0 to 200 mg/L-N (0 to 30˚C) | ±10% of reading or 2 mg/L-N, w.i.g. | T63<30 sec | 0.01 mg/L |
Barometric Pressure | Integral Barometer | 375 to 825 mmHg | ±1.5 mmHg from 0 to 50°C | - | 0.1 mmHg |
Blue-green Algae, | Total Algae Sensor SKU: 599102-01 | 0 to 100 μg/L; | Linearity: r2 >0.999 for serial dilution of Rhodamine WT solution across full range | T63<2 sec | 0.01 μg/L; |
Blue-green Algae, | Total Algae Sensor SKU: 599103-01 | 0 to 280 μg/L; | Linearity: r2 >0.999 for serial dilution of Rhodamine WT solution acriss full range | T63<2 sec | 0.01 μg/L; |
Chloride | Chloride Sensor | 0 to 1,000 mg/L-Cl (0 to 30˚C) | ±15% of reading or ±5 mg/L-Cl, w.i.g. | T63<30 sec | 0.01 mg/L |
Chlorophyll | Total Algae Sensor | 0 to 400 μg/L Chl; | Linearity: r2 >0.999 for serial dilution of Rhodamine WT solution across full range | T63<2 sec | 0.01 μg/L Chl; |
Conductivity1 | Wiped Conductivity / Temperature Sensor | 0 to 100 mS/cm | ±1% of reading or 2 µS/cm, w.i.g | T95<30 sec | 0.001 to 0.01 mS/cm (range dependent) |
Depth - 10 m | Integral, Non-vented Depth Sensor3 | 0 to 10 m | ±0.04% FS (±0.004 m or ±0.013 ft) | T63<2 sec | 0.001 m (0.001 ft) |
Depth - 100 m | Integral, Non-vented Depth Sensor3 | 0 to 100 m | ±0.04% FS (±0.04 m or ±0.13 ft) | T63<2 sec | 0.001 m (0.001 ft) |
Depth - 250 m | Integral, Non-vented Depth Sensor3 | 0 to 250 m | ±0.04% FS (±0.10 m or ±0.33 ft) | T63<2 sec | 0.001 m (0.001 ft) |
Dissolved Oxygen, % air saturation | Optical Dissolved Oxygen Sensor | 0 to 500% | 0 to 200%: ±1% of reading or 1% saturation, w.i.g.; | T63<5 sec5 | 0.1% air saturation |
Dissolved Oxygen, mg/L | Optical Dissolved Oxygen Sensor | 0 to 50 mg/L | 0 to 20 mg/L: ±0.1 mg/L or 1% of reading, w.i.g.; | T63<5 sec5 | 0.01 mg/L |
fDOM | fDOM Sensor | 0 to 300 ppb Quinine Sulfate equivalents (QSU) | Linearity: r2 > 0.999 for serial dilution of 300 ppb QS solution | T63<2 sec | 0.01 ppb QSU |
Level, Vented - 10 m | Integral Vented Level Sensor | 0 to 10 m (0 to 33 ft) | ±0.03% FS (±0.003 m or ±0.010 ft) | T63<2 sec | 0.001 m (0.001 ft) |
Nitrate | Nitrate Sensor | 0 to 200 mg/L-N (0 to 30˚C) | ±10% of reading or ±2 mg/L-N, w.i.g. | T63<30 sec | 0.01 mg/L |
pH | pH Sensor | 0 to 14 units | ±0.1 pH units within ±10˚C of calibration temperature; | T63<3 sec8 | 0.01 units |
ORP | pH/ORP Sensor | -999 to 999 mV | ±20 mV in Redox standard solution | T63<5 sec6 | 0.1 mV |
Temperature | Wiped Conductivity / Temperature Sensor | -5 to 50°C | ±0.2°C2 | T95<30 sec | 0.001 °C |
Turbidity9 | Turbidity Sensor | 0 to 4000 FNU | 0 to 999 FNU: 0.3 FNU or ±2% of reading, w.i.g.; | T63<2 sec | 0 to 999 FNU: 0.01 FNU |
Salinity | Calculated from Conductivity and Temperature11 | 0 to 70 ppt | ±1.0% of reading or 0.1 ppt, w.i.g. | T63<2 sec | 0.01 ppt |
Specific Conductance | Calculated from Conductivity and Temperature11 | 0 to 200 mS/cm | ±0.5% of reading or 0.001 mS/cm, w.i.g. | - | 0.001, 0.01, 0.1 mS/cm |
Total Dissolved Solids (TDS) | Calculated from Conductivity and Temperature11 | 0 to 100,000 mg/L | Not Specified | - | Variable |
Total Suspended Solids (TSS) | Calculated from Turbidity and user reference samples | 0 to 1500 mg/L | Not specified | T63<2 sec | Variable |
**Specifications indicate typical performance and are subject to change. All sensors have a depth rating to 250 m (820 ft), except shallow and medium depth sensors, ammonium, chloride, and nitrate. Accuracy specification is attained immediately following calibration under controlled and stable environmental conditions. Performance in the natural environment may vary from quoted specification.
w.i.g. = whichever is greater
EXO sensors are not compatible with YSI 6-Series sondes, sensors, or handheld.
1Outputs of specific conductance (conductivity corrected to 25˚C) and total dissolved solids are also provided. See Calculated Parameters and footnote 11.
2 Temperature accuracy traceable to NIST standards
3Accuracy specifications apply to conductivity levels of 0 to 100,000 μS/cm.
4 Relative to calibration gases
5 When transferred from air-saturated water to stirred deaerated water
6 When transferred from water-saturated air to Zobell solution
7Within the environmental pH range of pH 4 to pH 10.
8On transfer from water-saturated air to rapidly stirred air-saturated water at a specific conductance of 800 μS/cm at 20˚C; T63<5 seconds on transfer from water-saturated air to slowly-stirred air-saturated water.
9 Calibration: 1-, 2-, or 3-point, user-selectable
10 Performance based on 3-point calibration done with YSI AMCO-AEPA standards of 0, 124, and 1010 FNU. The same type of standard must be used for all calibration points.
11 Values are automatically calculated from conductivity according to algorithms found in Standard Methods for the Examination of Water and Wastewater (Ed. 1989).
Xenoy is a trademark of SABIC Innovative Plastics IP BV.
EXO Bluetooth modules comply with Part 15C of FCC Rules and have FCC, CE Mark and C-tick approval. Bluetooth-type approvals and regulations can be country specific. Check local laws and regulations to insure that the use of wireless products purchased from Xylem are in full compliance.