EXO2 Multiparameter Sonde

The EXO advanced water quality monitoring platform includes the versatile multiparameter EXO2 sonde for oceanographic, estuarine, or surface water applications.

Technical specification (PDF)

Key Benefits
• High-accuracy sensors with on-board memory
• Wireless communications
• Seamless integration into marine, estuarine, freshwater and ground water monitoring systems

Smart Sondes and Sensors
Extremely versatile instrument, allowing the user to automatically configure a sonde with different sensor for different applications in minutes

Tested in a variety of rigorous field conditions as well as lab conditions to ensure accuracy and response times

Monitor without Interruption
No matter which EXO sensors users select, other features of the sensors’ design make them rugged and durable:

• Wet-mateable connectors resist corrosion
• Isolated components prevent short circuits
• Welded housings and double o-rings prevent leaks
• High-impact plastic and titanium resists breaking
• Built-in antifouling systems protect data integrity
• Low power consumption extends underwater deployments

Anti Fouling Central Wiper
Depth / Pressure Rating / Limit 0 to 250 m (0 to 820 ft)
Desktop Software Compatible Yes
Flow Cell Yes
Languages German, English, French, Japanese, Chinese, Spanish
Logging Capabilities Yes
Medium Fresh, sea or polluted water
Memory >1,000,000 logged readings, 512 MB total memory
Monitoring Yes
Multiparameter Yes
Operating Temperature -5 to +50°C
Power 4 Alkaline Batteries
Sampling Yes
Smart Sensors / Ports Yes
Storage Temperature -20 to +80°C
Unit of Measure Parameter Dependent
User Calibratable Yes
Waterproof Yes
EXO2 Specifications
Battery Life 90 days*
Communications Computer Interface: Bluetooth wireless technology (between sonde and handheld or computer with KOR software), USB
Output Options: USB with signal output adapter (SOA); RS-232 & SDI-12 with DCP-SOA.
Diameter 7.62 cm (3.00 in)
Length 71.10 cm (28.00 in)
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)
Warranty: 3 mos Replaceable reagent modules for ammonium, chloride, and nitrate
Warranty: 1 yr Optical DO membranes and replaceable reagent modules for pH and pH/ORP
Warranty: 2 yrs Cables; sonde bulkheads; handheld; conductivity, temperature, depth, and optical sensors; electronics base for pH, pH/ORP, ammonium, chloride, and nitrate sensors; and accessories
Weight 3.60 kg (7.90 lbs)

*Typically 90 days at 20˚C at 15-minute logging interval; temperature/conductivity, pH/ORP, DO, total algae, and turbidity sensors installed with central wiper that rotates once per logging interval on EXO2. Battery life is heavily dependent on sensor configuration.

EXO Parameter Measured Sensor** Range Accuracy Response Resolution
(freshwater only)
Ammonium Sensor
Ammonia with pH sensor
SKU: 599710
0 to 200 mg/L (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;
0 to 100 RFU;
Linearity: R2 >0.999 for serial dilution of Rhodamine WT solution from 0 to 100 μg/mL BGA-PC equivalents T63<2 sec 0.01 μg/L;
0.01 RFU
Blue-green Algae,
Total Algae Sensor

SKU: 599103-01
0 to 280 μg/L;
0 to 100 RFU;
Linearity: R2 >0.999 for serial dilution of Rhodamine WT solution from 0 to 280 μg/mL BGA-PE equivalents T63<2 sec 0.01 μg/L;
0.01 RFU
(freshwater only)
Chloride Sensor
SKU: 599711
0 to 18000 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;
0 to 100 RFU
Linearity: R2 >0.999 for serial dilution of Rhodamine WT solution from 0 to 400 μg/L Chl a equivalents T63<2 sec 0.01 μg/L Chl;
0.01 RFU
Conductivity1 Conductivity / Temperature Sensor
SKU: 599870
0 to 200 mS/cm 0 to 100: ±0.5% of reading or 0.001 mS/cm, w.i.g.;
100 to 200: ±1% of reading
T63<2 sec 0.0001 to 0.01 mS/cm (range dependent)
Depth – 10 m Integral, Non-vented Depth Sensor3 0 to 10 m
(0 to 33 ft)
±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 to 328 ft)
±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 to 820 ft)
±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
SKU: 599100-01
0 to 500%
air saturation
0 to 200%: ±1% of reading or 1% saturation, w.i.g.;
200 to 500%: ±5% of reading 4
T63<5 sec5 0.1% air saturation
Dissolved Oxygen, mg/L Optical Dissolved Oxygen Sensor
SKU: 599100-01
0 to 50 mg/L 0 to 20 mg/L: ±0.1 mg/L or 1% of reading, w.i.g.;
20 to 50 mg/L: ±5% of reading 4
T63<5 sec5 0.01 mg/L
fDOM Sensor
SKU: 599104-01
0 to 300 ppb Quinine Sulfate equivalents (QSU) Linearity: R2 > 0.999 for serial dilution of 300 ppb QS solution
Detection Limit: 0.07 ppb QSU
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)
(freshwater only)
Nitrate Sensor
SKU: 599709
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
SKU:599701 guarded599702 unguardedpH/ORP Sensor
SKU:599705 guarded599706 unguarded
0 to 14 units ±0.1 pH units within ±10˚C of calibration temp;
±0.2 pH units for entire temp range7
T63<3 sec8 0.01 units
ORP pH/ORP Sensor
SKU:599705 guarded,
599706 unguarded
-999 to 999 mV ±20 mV in Redox standard solution T63<5 sec6 0.1 mV
Temperature Conductivity / Temperature Sensor
SKU: 599870
-5 to 35°C
35 to 50°C
T63<1 sec 0.001 °C
Turbidity9 Turbidity Sensor
SKU: 599101-01
0 to 4000 FNU 0 to 999 FNU: 0.3 FNU or ±2% of reading, w.i.g.;
1000 to 4000 FNU: ±5% of reading10
T63<2 sec 0 to 999 FNU = 0.01 FNU;
1000 to 4000 FNU = 0.1 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 .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
Cal constant range
0.30 to 1.00
(0.64 default)
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.