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EXO2 Water Quality Sonde

Product Recycling Recycling

Collect data to 250 m with the advanced EXO2 sonde – six replaceable smart sensors and a central wiper to clean biofouling.

This product is RoHS Compliant
 EXO2 water quality sonde from YSI
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YSI has Authorized Distributors all over the globe. View a map and find your closest contact for YSI EXO2 Water Quality Sonde products and accessories.

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Have a question about your YSI EXO2 Water Quality Sonde? Check out the support page with resources compiled just for you.

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Want to return a product for service? Here you'll find authorized service centers and instructions on how to send in your YSI EXO2 Water Quality Sonde.

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For complete information about the EXO platform--including videos, articles, parts guide, manual and software--visit


The EXO2 water quality sonde is a new YSI multiparameter instrument that collects data with six user-replaceable sensors, a central wiper to keep sensors clean of biofouling, and an integral pressure transducer for depth.

Smart Ports: Each sensor port on the sonde accepts any EXO water quality sensor and automatically recognizes it.

Sensor Options:

  • Conductivity and Temperature
  • Dissolved Oxygen (optical)
  • fDOM (Fluorescent Dissolved Organic Matter, surrogate for CDOM)
  • pH or pH / ORP
  • Depth (integral)
  • Total Algae (Dual-channel Chlorophyll and Blue-green Algae)
  • Turbidity

Data Collection Options:

  • Store onboard the sonde
  • Transfer data to DCP
  • Relay data to PC
  • Relay data to EXO Handheld

For a list of EXO instruments, accessories, and replacement parts, browse

For information on preventive maintenance and repair programs, review the EXO Service Plan flyer.




The EXO2 with
  • 7 sensor ports (6 ports available for sensors when central wiper used)
  • Integral pressure transducer
  • 1 peripheral port for power communication
  • 1 peripheral port for auxiliary sensor
  • Depth: 820 ft, 250 m

    Medium Fresh, sea or polluted water
    Temperature Operating
    -5 to +50°C
    -20 to +80°C

    Bluetooth wireless technology; USB cable

    RS-485, RS-232, SDI-12

    Software KOR®
    Dimensions Diameter
    Length, no depth
    3.00 in, 7.62 cm
    28.00 in, 71.10 cm
    3.60 kg, 7.90 lbs (batteries and sensors installed)
    Power External
    9 to 16.5 V DC
    4 D-size alkaline batteries

    Memory 512 MB; >1,000,000 logged readings

    Ratings CE, UL, RoHS, WEEE

    Tips, FAQs & Guides

    Storm3 & EXO2 Webinar Slides

    Catalogs & Brochures

    Aquaculture Applications, Capabilities & Solutions

    Español - Piscicultura Aplicaciones, Competencia y Soluciones

    Water Monitoring Solutions

    EXO Preventive Maintenance & Training Programs

    EXO Advanced Water Quality Monitoring Platform

    News Briefs

    EXO fDOM Assessment

    EXO Total Algae Sensor Combines Blue-green Algae and Chlorophyll Measurements

    Annual Sonde Maintenance Program

    Application Notes

    Sellafield and EXO, Monitoring Nuclear Waste


    Archived Webinar:
    5 Costly Mistakes with Sondes (...and How Training Can Help!)

    Original Broadcast: Thursday, December 4th, 2014 —2:00 pm - 2:45 pm EDT, USA

    Brandon and Patrick will reveal some of the most frequently seen mishaps in respect to Calibration, Hardware Setup, Maintenance, and more. Learn how your team can avoid these common pitfalls, and discover how YSI's new online training portal, EXO University, can help you achieve your monitoring goals.

    Support Materials:

    EXO University

    Calibration Solutions - Expiration Dates [PDF]

    fDOM Surrogate Measurements Study [PDF]

    Archived Webinar:
    Expert Tips for Continuous Water Quality Monitoring: Featuring Dustin Shull, Pennsylvania DEP

    Original Broadcast: September 30th, 2014 —1 PM CST (2 PM EST)

    Information is power... to better manage our water resources. On September 30th, join our group of water quality monitoring experts as they share strategies for turning continuous data from your unattended monitoring stations into water quality insight.

    Join our featured speaker Dustin Shull as he shares results and lessons learned from the Pennsylvania Continuous In-stream Monitoring (CIM) program. Learn how you can reliably collect continuous data for the most common water quality parameters using EXO instrumentation, while cutting maintenance costs and site visits. Discover how to leverage AQUARIUS Time-Series software to process and analyze your water quality data as well.

    1-Hour Webinar Highlights Include:

    • 3 steps to continuous water quality monitoring
    • Tricks for data collection, QC checking & calibration
    • Site selection considerations for high quality data
    • How to correct, analyze, visualize & report on continuous data
    • Lessons learned: dams, acid, sediment, seasonality, & ammonia
    • 6 tips for success

    > Watch a recording of the live event.

    Support Materials:

    Archived Webinar:
    A Simple Guide to Collecting Water Quality Data: EXO2 Sonde & Storm 3 Data Logger

    Original Broadcast: Thursday, June 26th —1:00 - 1:45 PM EDT, USA

    Note: Best picture quality can be achieved by selecting the tool icon in the YouTube player, lower right corner, and selecting 720p or 1080p.

    Setting up your own long-term water monitoring station doesn't have to be a headache. Take some time to join us for our "A Simple Guide to Collecting Water Quality Data" webinar where we will share how easy it can be to set up a real-time water quality system.

    In this webinar you will learn about the following:

    • The benefits of a real-time monitoring site
    • Wiring up a Data Logger and Sonde
    • Configuring parameters and addresses
    • Activating Wi-Fi
    • Viewing real-time data with Storm Central™

    Support Materials:

    • 6 Steps To Select the Best Datalogger for Your Application

     YSI Solution Expiration Dates [PDF]

    • Webinar Slides with Notes [PDF]

    Archived Webinar:
    Top 5 Challenges to Collecting Water Quality Data: How New Technology Is Tackling Big Issues

    Original Broadcast: September 12, 2013 —1:00-1:30 PM Eastern time (US)

    This webinar examines the common problems faced by the monitoring community; why they are problems; and what solutions the instrumentation industry offers to counter the problems.

    Typical frustrations include:

    1. Ongoing repair & maintenance costs eat up my budget. Why can't field instruments last longer?
    2. Uncertainty with future projects, legislation, & technology keep my program in flux. Which instrument can I rely on for the next decade?
    3. Incomplete or inaccurate data wastes my time. I need data quality assurances.
    4. Shrinking budgets compromise my program's goal. How can we be more efficient with what we have?
    5. Training employees on instrumentation shouldn't be rocket science. How can the industry make this easier?

    Who should attend:
    Those dedicated to monitoring natural aquatic environments, such as rivers, lakes, wetlands, oceans, estuaries, and ground water.

    YSI product managers Tim Finegan and Brandon Smith discuss the topics commonly voiced by the customer and water instrumentation user and offer insight and solutions into these issues.

    Archived Webinar:
    Water Quality Data Collection Made Easy: A Practical Solution for Continuous Monitoring

    Original Broadcast: April 26, 2013 —1:00-2:00 PM Eastern Time (USA)

    Learn how to easily conduct continuous water quality monitoring in real-time by using two new powerful tools: EXO & STORM.

    This informative web presentation discusses:

    • The benefits of the combined EXO water quality sonde and versatile STORM telemetry solution for remote monitoring
    • How EXO can reduce your operations and maintenance costs through longer deployments between servicing
    • An "eyes on your data" solution to capture episodes with high-resolution and better manage your water quality program

    The EXO + STORM solution makes it easy to do real-time continuous monitoring and share your data via the web. You can set up this plug-and-play solution in under 30 minutes.

    Our presenters have years of real-world field experience and will provide examples of actual water quality monitoring stations that have implemented the EXO + STORM solution.

    Archived Webinar:
    Get More Accurate Estimates of Total Algae Biomass: A New Tool for the Concurrent Measurement of Chlorophyll & Cyanobacteria

    Original Broadcast: March 29, 2013 —1:00 PM - 1:45 PM EST (USA)

    This webinar will discuss the sensor technology, practical-use applications, and calibration of the EXO Total Algae Sensor from YSI.

    Topics include:

    1. Why measuring Chlorophyll & Blue-green Algae (cyanobacteria) together is useful for an accurate estimate of total algae biomass
    2. Total Algae Sensor technology
    3. Applications for total algae measurements:

    o Eutrophication of surface water
    o Coastal algae blooms
    o Drinking water reservoirs

    4. Interferences with TAL sensor
    5. Calibration and correlation to lab samples
    6. Q&A

    Archived Webinar:
    A Closer Look at fDOM Measurement

    Original Broadcast: February 26, 2013 —1:00 PM - 1:45 PM EST

    Listen to an informative webinar about measuring dissolved organic matter in surface water using YSI's newest smart sensor, fDOM.

    We discuss topics including:

    • What is fDOM?
    • How does field fDOM measurement work?
          - Details on YSI's EXO fDOM sensor
    • Applications for fDOM measurement with EXO, including:
         - Augmented sensor suite for enhanced ecosystem monitoring
         - Proxy for DOM/DOC/TOC, land-derived nutrients and contaminants
         - Light attenuation and primary productivity studies 
    • Interpreting fDOM data and interferences
    • Benefits of combining fDOM with other water quality sensors

    Archived Webinar:
    New Trends in Environmental Monitoring: Breaking the Sonde Barrier with the EXO Advanced Water Quality Platform

    Original Broadcast: Aug. 31, 2012 —1-2 PM EDT

    Water quality assessment has moved steadily from spot sampling to continuous monitoring---requiring tougher instruments, smarter sensors, and greater ease-of-use in the collection and transmission of data from remote sites.

    Breaking onto the scene is the new EXO technology for long-term environmental monitoring from YSI. In this 45-minute web seminar, you will learn about:

    . Reducing Operations and Maintenance Costs with quicker calibration procedures using Bluetooth wireless communication, smart sensors that retain their calibration metadata, and concurrent calibrations with a single reagent pour.

    . Longer Deployment Times with rugged, industry-leading materials and advancements in biofouling protection.

    . Increased Data Quality with intelligent sensor technology and smart QC. 

    . Greater Monitoring Flexibility with universal sensor ports and enhanced sampling modes.

    Learn why now is the right time to consider the EXO platform as a way to break free from traditional data sondes.

    Who should attend?
    Those dedicated to monitoring natural aquatic environments, such as oceans, estuaries, rivers, lakes, and ground water.


    Antifouling Screen for Conductivity-Temperature (CT) Sensor

    Anti-fouling Sensor Screen

    Copper-mesh screens block organisms and provide biofouling protection for the 6560 Conductivity-Temperature probe, 599870 Conductivity-Temperature probe and non-wiped pH probes.

    Copper Antifouling Sonde Guard for YSI 600OMS Sonde

    Anti-fouling Sonde Guards

    Copper-alloy sonde guards protect water quality sensors and provide biofouling protection for YSI Sondes.





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