About Us

YSI offers a full line of environmental monitoring and sampling instruments, systems, and services for water quality and water velocity data. Our multiparameter instruments, aquaculture monitoring systems, handheld sampling instruments, and complete line of SonTek products can be incorporated into any of your monitoring or sampling applications.

Whether it's a field application for surface water, groundwater, wastewater, coastal/oceans or aquaculture, YSI products are designed to exceed your expectations. YSI also offers a line of laboratory instruments.

Measure dissolved oxygen, pH, ORP, conductivity, chlorophyll, blue-green algae, ammonium, nitrate, chloride and much more with YSI.

	When it comes to dissolved oxygen measurement, YSI offers more knowledge, more experience and more technology options than any other company. We hope you find this resource page helpful and informative. Visit it frequently. After all, "We Know DO™". To Learn More, Click Here.
	YSI groundwater instruments can be used with flow cells to easily pump water through the cell to provide continuous flow past the probes preventing placing instruments into the well. Measure dissolved oxygen, level, pH, ORP, conductivity, salinity, temperature or turbidity easily and accurately. To Learn More, Click Here.
	YSI instrument can be used for wastewater sampling and monitoring for process productivity and laboratory testing. Handheld or unattended instruments are available for spot sampling dissolved oxygen, pH, ammonium, and ORP. To Learn More, Click Here.
	Whether you conduct laboratory analysis for BOD, dissolved oxygen, pH, or conductivity, YSI lab products will make your job easier. To Learn More, Click Here.
	Tighter government restrictions, higher quality standards and production costs, and scarce water supplies are evident now and will continue into the future. YSI is committed to providing cost-effective aquaculture monitoring and sampling solutions to help you meet these challenges. Our water quality technologies offer real advantages that result in real savings. To Learn More, Click Here.
	Sampling, monitoring, and logging data in surface water applications, ranging from ponds to streams and rivers to wetlands and estuaries. Trust YSI instruments to meet the demands of a true field-worthy water quality instrument. To Learn More, Click Here.

Click Here To Download:
•Video: YSI Pro20 Dissolved Oxygen Meter
•Video: YSI ProODO Optical Dissolved Oxygen Meter
•Video: YSI Professional Plus Multiparameter Meter
•Video: CastAway Castable CTD Instrument
•Video: 550A Dissolved Oxygen Meter Calibration
•Video: Pro20 Handheld Dissolved Oxygen Meter Initial Setup
•Video: Pro20 Handheld Dissolved Oxygen Meter Calibration
•Video: Pro20 DO Sensor Installation
•Video: Professional Plus Ordering Guide
•The Dissolved Oxygen Handbook
•Brochure: YSI BOD Testing

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• YSI IQ SensorNet 2020 XT
• Multiparameter Monitoring Systems
• BOD Analyst Pro Software
• Pro2030 Handheld DO/Conductivity Instrument
• Fast-Response pH Sensor
• ProOBOD Optical BOD Probe
• CastAway Castable CTD Instrument
• ProODO Handheld Optical Dissolved Oxygen Meter
• Professional Plus Handheld Multiparameter Instrument
• Pro20 Handheld Dissolved Oxygen Instrument
• 9300 / 9500 Photometer
• 556MPS Handheld Multiparameter Instrument
• 550A Dissolved Oxygen Instrument
• 5000 / 5100 Advanced Dissolved Oxygen Instruments For The Lab
• Level Scout®
• pH10 Pen-Style pH Instrument
• 6920 V2 Sonde

• How One Wastewater Treatment Plant Saved Time And Money Measuring Turbidity And TSS
• YSI Introduces Online Water Quality Instrumentation — Ideal For Municipal Wastewater Utilities
• YSI Donation To Freshwater Institute Helps Protect And Restore Healthy Populations Of Salmon By Pioneering Safer, Cleaner Approaches To Land-Based Salmon Farming
• University Of Georgia And Yale University Receive YSI "Minding The Planet" Grants
• Water Quality Is Key To The Success Of Cardiff Bay Restoration
• Network Monitors Water Quality In Shale Gas Drilling Region
• Source Water Monitoring Case Studies And Solutions
• Application Note: Dairy Farms Use YSI Instruments To Map Volume Of Wastewater Lagoons
• Application Note: Employing Best Water Quality Monitoring Practices To Reduce Runoff During Construction
• Bathymetric Survey Of Remote Lakes Collects High-Resolution Data For Impact Model Of Hydroelectric Plant
• Real-Time Monitoring–Through Swell And High Water
• Fish Diversity, Nutrient Recycling And Periphyton Productivity In The Littoral Zone Of Lake Tanganyika
• YSI Webinar: Making Better pH Measurements In Sampling And Long-Term Monitoring Applications
• YSI Webinar: Set Up Floating Platforms For Lake, Estuary And Tidal Monitoring of Water Quality Parameters
• Continuous Monitoring Of Turbidity In Ohio Rivers Using Modified Sidestream Method
• Vertical Profiling Safeguards Drinking Water And Sheds Light On Cyanobacteria
• Desalination Plants: YSI Instruments Monitor Flow & Water Quality At Multiple Stages
• Using Real-Time Telemetry For Ecological Monitoring Of Coastal Wetlands
• Using A YSI Multiparameter Handheld Instrument To Monitor The Effects Of A Forest Invader
• Baltimore Harbor WATERKEEPER Recipient Of YSI Foundation Grant
• YSI Webinar: Making Better Turbidity Measurements in Ambient Water
• YSI Announces Optical BOD Webinar Introducing Optical BOD Technology
• YSI Luminescent Dissolved Oxygen Sensors Meet ASTM D888-09 Test Method
• University Of West Florida Receives Grant For Water Quality Research
• Turbidity Monitoring Buoy Automates Reporting Requirements
• The EcoSense® pH10 Used In Science Fair Projects
• The Newport Aquarium’s WAVE Foundation Uses YSI Instruments To Support Project Piaba
• Water Flows From The Golden Hills Of California
• YSI Level Scouts® Monitor Groundwater Levels To Help Protect The Great Sphinx
• J. Lohr Winery Utilizes YSI Instruments In Managing Dissolved Oxygen
• Busseron Creek Watershed Partnership Addresses Concerns In A Rural Watershed
• Miami Conservancy District Uses Nitrate Screening As Conjunctive Management Tool
• Small Team Saves Big Hassles With The Professional Plus Multiparameter Instrument
• Low-Flow Sampling Of Water Quality Parameters Used In Determining Groundwater Stability
• ECSI Manages Habitat In High Hydrogen Sulfide Environments With Optical DO