--- title: "YSI EXO Water Quality Sondes | Aethair" description: "YSI EXO and legacy 6-Series water-quality sondes in the Aethair sensor catalog: 16 models with up to 22 parameters, connected through Thiamis." url: https://aethair.io/sensors/ysi-water-quality-sondes/ --- Sensors · Water Quality Sondes # YSI EXO Water Quality Sondes YSI multiparameter water-quality sondes (Xylem): the current EXO platform and the legacy 6-series ('Sonde 6'). Interchangeable smart sensors for temperature, conductivity/salinity, pH/ORP, dissolved oxygen (optical ODO on EXO), turbidity, chlorophyll/blue-green algae, fDOM, depth, and ISEs; EXO adds an anti-fouling central wiper on the larger models. The driver maps generic channels to each sonde's enabled sensors. [Schedule a call](https://calendly.com/d/ctdd-mkr-v9v/aethair-demo-website) [Build a Configuration](https://aethair.io/build/?params=water_temperature,conductivity,specific_conductance,salinity,tds,ph,orp,do) At a glance **22** parameters **16** models [**Connects via Thiamis** RS-232 · ASCII · SDI-12](https://aethair.io/products/thiamis/) 2 standards limit what it measures - [EPA drinking water EPA National Drinking Water Standards](https://aethair.io/standards/epa_ndwr/) - [EPA aquatic life EPA Ambient Water Quality Criteria (Aquatic Life)](https://aethair.io/standards/epa_aquatic_life/) Measures ## What the YSI EXO Measures 22 parameters, each linked to its page: the sensors, units, and standards behind it. [Water Temperature °C / °F / K](https://aethair.io/parameters/water_temperature/) [Conductivity mS/cm / µS/cm](https://aethair.io/parameters/conductivity/) [Specific Conductance mS/cm / µS/cm](https://aethair.io/parameters/specific_conductance/) [Salinity ppt](https://aethair.io/parameters/salinity/) [TDS g/L / kg/L / mg/L](https://aethair.io/parameters/tds/) [pH pH / mV](https://aethair.io/parameters/ph/) [ORP mV](https://aethair.io/parameters/orp/) [Dissolved Oxygen %Sat / mg/L / %Sat Local](https://aethair.io/parameters/do/) [Turbidity NTU / FNU / Raw](https://aethair.io/parameters/turbidity/) [TSS mg/L / g/L](https://aethair.io/parameters/tss/) [Chlorophyll µg/L / RFU / Raw](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae RFU / µg/L / Raw / cells/mL](https://aethair.io/parameters/bga/) [fDOM / CDOM RFU / QSU / Raw](https://aethair.io/parameters/fdom/) [Nitrate (NO₃) mg/L / mV](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄) mg/L / mV](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃) mg/L](https://aethair.io/parameters/ammonia/) [Chloride mg/L / mV](https://aethair.io/parameters/chloride/) [Water Level / Depth m / ft](https://aethair.io/parameters/water_level/) [Water Pressure psia / psig](https://aethair.io/parameters/water_pressure/) [Resistivity MΩ·cm / kΩ·cm / Ω·cm](https://aethair.io/parameters/resistivity/) [Ion-Selective (Other Ions) µg/L](https://aethair.io/parameters/ion/) [PAR (Photosynthetically Active Radiation) µmol/s/m²](https://aethair.io/parameters/par/) [Connects via **Thiamis**](https://aethair.io/products/thiamis/) Wired interfaces [RS-232 ASCII](https://aethair.io/products/thiamis/#port-rs232) [SDI-12](https://aethair.io/products/thiamis/#port-sdi-12) Models ## YSI EXO Models 16 models, each with what it measures and the ranges its datasheet gives. | Model | Description | Measures & specs | | - | - | - | | **EXO1** | 4-port sonde with internal D-cell battery for autonomous logging; slim 4.7 cm (1.85 in) body for narrow wells and profiling. No central wiper (not wiper-compatible). | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [TSS](https://aethair.io/parameters/tss/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [fDOM / CDOM](https://aethair.io/parameters/fdom/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **EXO1S** | EXO1 without the internal battery compartment: shorter and lighter, externally powered (handheld, KorLink, or logger). Same 4 ports; no central wiper. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [TSS](https://aethair.io/parameters/tss/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [fDOM / CDOM](https://aethair.io/parameters/fdom/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **EXO2** | 7-port flagship (6 sensor ports plus a central anti-fouling wiper port) with internal battery; built for long-term unattended monitoring in high-fouling water. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [TSS](https://aethair.io/parameters/tss/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [fDOM / CDOM](https://aethair.io/parameters/fdom/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **EXO2S** | EXO2 without the internal battery compartment, an externally powered variant; same 7 ports and central-wiper support. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [TSS](https://aethair.io/parameters/tss/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [fDOM / CDOM](https://aethair.io/parameters/fdom/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **EXO3** | 5-port hybrid (4 sensor ports plus a central wiper port) with internal battery and native SDI-12; EXO2 wiper protection in a slimmer 7.62 cm body. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [TSS](https://aethair.io/parameters/tss/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [fDOM / CDOM](https://aethair.io/parameters/fdom/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **EXO3S** | EXO3 without the internal battery compartment: externally powered; native SDI-12 and central-wiper support. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [TSS](https://aethair.io/parameters/tss/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [fDOM / CDOM](https://aethair.io/parameters/fdom/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **6600 V2** | Large multi-parameter sonde for long-term monitoring, with a central anti-fouling wiper. The V2-2 runs two of the six optical sensors at once and the V2-4 runs four; carries an internal battery for autonomous logging. Discontinued (succeeded by EXO2). | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **6600EDS V2** | 6600 V2-2 Extended Deployment System: central-wiper sonde with the same two-optical-sensor capacity, built for extended unattended deployments. Discontinued. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **6920 V2** | Mid-size multi-parameter sonde. The V2-1 accepts one optical sensor; the V2-2 accepts two. Internal battery for logging. Discontinued (succeeded by EXO3). | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **6820 V2** | Mid-size multi-parameter sonde, externally powered (no internal battery). The V2-1 accepts one optical sensor; the V2-2 accepts two. Discontinued. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **600 OMS V2** | Compact optical monitoring sonde: temperature and dissolved oxygen with one optical port (typically turbidity or blue-green algae). Battery and non-battery versions. Discontinued. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **600XL** | Compact sonde: temperature, conductivity, dissolved oxygen, and pH/ORP. Externally powered. Discontinued. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **600XLM** | 600XL with internal datalogging memory and battery for standalone deployments. Discontinued. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **600LS** | Compact sonde with a vented level/depth sensor plus temperature, conductivity, dissolved oxygen, and pH/ORP. Discontinued. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **600R** | Compact rugged sonde: temperature, conductivity, dissolved oxygen, and pH/ORP; externally powered. Discontinued. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | | **600QS** | Compact QuickSample sonde for spot sampling: temperature, conductivity, dissolved oxygen, and pH/ORP. Discontinued. | [Water Temperature](https://aethair.io/parameters/water_temperature/) [Conductivity](https://aethair.io/parameters/conductivity/) [Specific Conductance](https://aethair.io/parameters/specific_conductance/) [Resistivity](https://aethair.io/parameters/resistivity/) [Salinity](https://aethair.io/parameters/salinity/) [TDS](https://aethair.io/parameters/tds/) [pH](https://aethair.io/parameters/ph/) [ORP](https://aethair.io/parameters/orp/) [Dissolved Oxygen](https://aethair.io/parameters/do/) [Turbidity](https://aethair.io/parameters/turbidity/) [Chlorophyll](https://aethair.io/parameters/chlorophyll/) [Blue-Green Algae](https://aethair.io/parameters/bga/) [Ion-Selective (Other Ions)](https://aethair.io/parameters/ion/) [Nitrate (NO₃)](https://aethair.io/parameters/nitrate/) [Ammonium (NH₄)](https://aethair.io/parameters/ammonium/) [Dissolved Ammonia (NH₃)](https://aethair.io/parameters/ammonia/) [Chloride](https://aethair.io/parameters/chloride/) [PAR (Photosynthetically Active Radiation)](https://aethair.io/parameters/par/) [Water Level / Depth](https://aethair.io/parameters/water_level/) [Water Pressure](https://aethair.io/parameters/water_pressure/) | Standards ## Standards for What It Measures Standards that set limits on the parameters it reports. [EPA drinking water EPA National Drinking Water Standards 5 of its parameters](https://aethair.io/standards/epa_ndwr/) [EPA aquatic life EPA Ambient Water Quality Criteria (Aquatic Life) 2 of its parameters](https://aethair.io/standards/epa_aquatic_life/) Solutions ## Where the YSI EXO Is Used Solutions whose recommended configuration uses this instrument or whose standards it is built to, followed by solutions whose core panel it partly measures. ### [Water Quality Monitoring](https://aethair.io/solutions/water-quality/) Rivers, lakes, drinking water, and stormwater ### [Aquaculture & Fish Farming](https://aethair.io/solutions/aquaculture/) Dissolved oxygen, temperature, and ammonia control ### [Hydrology, Level & Flow](https://aethair.io/solutions/hydrology/) Flood warning, stream gauging, and groundwater On the platform ## What the YSI EXO Gets From Aethair Connected through Thiamis, its readings arrive in the same Environet account as Aethair's own monitors. ### [Live data and alerts](https://aethair.io/platform/environet/) [Environet](https://aethair.io/platform/environet/) shows the instrument live and alerts the people you choose by email, SMS, and webhook, at the thresholds you set. [Noesis](https://aethair.io/platform/noesis/) sets up a dashboard, a report, or an alert from a plain-text request. ### [Compliance reports](https://aethair.io/platform/reports/) [Aethair Reports](https://aethair.io/platform/reports/) produces scheduled or on-demand reports from the instrument's readings, as a PDF or secure link. Templates cover Aethair Blue, WELL v2, cabin air (ISO 23875), and the CMS-2567 healthcare codebook (ASHRAE 170), or you can report against custom limits such as OSHA PELs, NAAQS, EPA guidance, or your own program limits. ### [Dashboards and the app](https://aethair.io/platform/dashboards/) Environet dashboards and the [Aethair App](https://aethair.io/platform/app/) show the instrument's readings just like any Aethair device. The occupant-facing [Aethair Dashboards](https://aethair.io/platform/dashboards/) status display is built around Aethair IAQ and Aethair PRO. Similar ## Other Water Quality Sondes ### [Eureka Water Probes](https://aethair.io/sensors/eureka-water-probes-water-quality-sondes/) [Water Quality Sondes](https://aethair.io/sensors/eureka-water-probes-water-quality-sondes/) [Eureka (Solinst) Manta+ multiparameter water-quality sondes: configurable sensor sets for…](https://aethair.io/sensors/eureka-water-probes-water-quality-sondes/) ### [In-Situ](https://aethair.io/sensors/in-situ-water-quality-sondes/) [Water Quality Sondes](https://aethair.io/sensors/in-situ-water-quality-sondes/) [In-Situ TROLL instruments: submersible (IP68) water-level and multiparameter loggers. Level TROLL…](https://aethair.io/sensors/in-situ-water-quality-sondes/) ### [Spectra Scientific](https://aethair.io/sensors/spectra-scientific-water-quality-sondes/) [Water Quality Sondes](https://aethair.io/sensors/spectra-scientific-water-quality-sondes/) [Spectra Scientific (spectrascientific.com) Spectra Litmus configurable multiparameter water-quality…](https://aethair.io/sensors/spectra-scientific-water-quality-sondes/) Questions ## YSI EXO FAQ How do EXO smart sensors and the sonde models relate? EXO Smart Sensors are interchangeable digital sensors that plug into any port, retain their own calibration, and work on every EXO sonde. The model sets only how many sensors run at once and whether a central anti-fouling wiper fits: EXO1/EXO1S have 4 ports (no central wiper), EXO3/EXO3S have 5 ports, and EXO2/EXO2S have 7 ports. So every model can measure the full parameter suite; the smaller sondes simply measure fewer parameters simultaneously. What is the difference between EXO1/2/3 and the 'S' versions? The S-series (EXO1S, EXO2S, EXO3S) is mechanically the same as EXO1/EXO2/EXO3 with identical ports and sensor support, but omits the internal D-cell battery compartment, so it is shorter and lighter and must be powered externally (handheld display, KorLink, or a data logger). Use the battery models for autonomous logging and the S-series for externally-powered continuous monitoring or spot sampling. Which anti-fouling wiper models are available? The EXO Central Wiper clears biofouling, sediment, and debris from the sensor faces during long deployments. It occupies the center port and can be fitted to the EXO2, EXO2S, EXO3, and EXO3S. It is not compatible with the EXO1 or EXO1S, which have no central port; those sondes rely on copper anti-fouling accessories (copper tape, C/T screen, guards, sleeves) instead. Why does one sensor report several parameters? Many EXO sensors output derived parameters alongside their primary reading. For example, the Conductivity/Temperature sensor yields temperature, conductivity, specific conductance, salinity, and total dissolved solids. The optical dissolved-oxygen sensor adds a local %-saturation reading, and turbidity derives total suspended solids. The Total Algae sensor pairs chlorophyll with either phycocyanin (TAL-PC) or phycoerythrin (TAL-PE), and the Ammonium ISE derives un-ionized ammonia (NH3) when a pH sensor is present. How is depth measured, and why is pressure also reported? Depth is measured by a non-vented pressure transducer built into the sonde body and does not occupy a sensor port. Pick the 10 m, 100 m, or 250 m range to match the deployment. The transducer's raw reading is reported as absolute pressure (psia/psig) and the sonde computes depth/level from it, so both a water-pressure and a water-level parameter are available. Nitrate, meanwhile, can be measured either by ion-selective electrode or by the NitraLED optical UV sensor; both report nitrate. How does the Thiamis integration read the sonde? The driver connects to the EXO serial output (9600 baud, 8-N-1) through a Signal Output Adapter: the DCP SOA for SDI-12/RS-232 or the Modbus SOA for RS-485. The EXO3/EXO3S provide native SDI-12, so they need no DCP SOA. It reads the sonde's serial number and firmware, then asks the sonde which parameters it is configured to output and logs those values each interval. The integration therefore ingests exactly the sensors installed and enabled on the sonde, so the parameter template set in KOR software controls what is recorded. How does the Thiamis integration read parameters from a 6-Series sonde? The driver polls the sonde over SDI-12 (1200 baud, 7-E-1) with the standard 'M' measurement command. The SDI-12 response is a bare, positional list of floating-point values with no per-value labels; the sonde does not send a header naming each reading. The integration therefore ingests the values as ordered channels and the meaning of each channel is fixed by the sonde's own configured sensor/parameter order, set in YSI's software (EcoWatch/6-Series) when the sonde is prepared. This page lists the full set of quantities a 6-Series sonde can report; a given deployment outputs only the sensors installed and enabled on that sonde. How many sensors can a sonde run at once? It depends on the number of optical ports. The 6820 V2-1 and 6920 V2-1 accept a single optical sensor; the 6600 V2-2, 6600EDS V2-2, 6820 V2-2, and 6920 V2-2 accept two; and the 6600 V2-4 accepts four. The optical family is turbidity, chlorophyll, rhodamine WT, blue-green algae PC, blue-green algae PE, and optical (ROX) dissolved oxygen, so the port count sets how many of these run simultaneously. The wet-chemistry electrodes (pH, ORP, conductivity, the nitrate/ammonium/chloride ISEs) and the depth transducer occupy their own dedicated ports. What is the difference between the dissolved-oxygen options? 6-Series sondes offer two DO technologies: the 6562 Rapid Pulse polarographic sensor and the 6150 ROX optical sensor. Both report dissolved oxygen as % air saturation and as mg/L; the optical ROX resists flow dependence and fouling for long deployments, while Rapid Pulse suits shorter or profiling work. On Aethair, both map to the single Dissolved Oxygen parameter. Is the 6-Series still available? No. YSI discontinued the 6-Series. Final sales ended between 2017 and 2018, and factory support ended in 2022–2023. It is superseded by the EXO platform (EXO1/EXO2/EXO3), which uses interchangeable smart sensors. The 6-Series remains in service in many long-running monitoring networks, which is why the driver is still maintained. Why are both a depth and a pressure reading available? The sonde carries a pressure transducer (vented on the 600LS 'level' sonde, non-vented on the others). Its raw reading is reported as absolute or gauge pressure (psia/psig), and the sonde derives depth or level in meters or feet from it, so both water-pressure and water-level parameters are available from one transducer. Sources: [www.ysi.com](https://www.ysi.com/products/multiparameter-sondes) · [www.ysi.com](https://www.ysi.com/File%20Library/Documents/Guides/EXO-Ordering-Guide.pdf) · [www.ysi.com](https://www.ysi.com/file%20library/documents/manuals/069300-ysi-6-series-manual-revj.pdf)