YSI utilizes a patented pulsed design with minimal surface area to provide stirring-independent dissolved oxygen readings. The Rapid Pulse DO sensor uses methods approved by both ASTM and the US EPA.

The 6-Series YSI 6150 ROX is a luminescent-based dissolved oxygen sensor that offers YSI customers a powerful tool for making long-term oxygen measurements in severe fouling and low oxygen environments. Its rugged design and large measurement range make it ideal for sampling, flow cell, and groundwater measurements.
The ROX optical sensor uses an integrated wiping system to provide anti-fouling in the most hostile environments.

Blue-green algae (a. k. a. cyanobacteria) monitoring is of growing interest due to the problems some species can present through the production of toxins and compounds that deteriorate the quality of drinking water and through the formation of blooms. Blue-green algae are of interest for ecosystem studies and monitoring as well, where they may represent the most abundant primary producer.

Blue-green algae (a. k. a. cyanobacteria) monitoring is of growing interest due to the problems some species can present through the production of toxins and compounds that deteriorate the quality of drinking water and through the formation of blooms. Blue-green algae are of interest for ecosystem studies and monitoring as well, where they may represent the most abundant primary producer.

The YSI 6025 Chlorophyll Probe expands YSI's suite of sensors for multi-parameter, water quality monitoring applications. The probe is designed to estimate phytoplankton concentrations by detecting the fluorescence from chlorophyll in situ. The data can be useful in predicting detrimental algae blooms and, indirectly, in determining nutrient loading in environmental applications. The probe features a mechanical self-wiping capability for long-term monitoring.
The YSI 6025 Chlorophyll Probe uses technology similar to that used by fluorometers, but the YSI sensor is much smaller, making it compatible with the probe ports in YSI's 6-Series instruments, including the YSI 6600 & 6600 V2 as well as the YSI 6820, 6820 V2, 6920, & 6920 V2. The YSI 6600 V2 sonde allows simultaneous measurement of four optical probes (dissolved oxygen, turbidity, chlorophyll, blue-green algae, and/or rhodamine), along with other parameters. The YSI 6820 V2 and 6920 V2 allow measurement of two optical probes, along with many other parameters.

In response to the need for accurate, in situ measurement of Rhodamine WT for water and pollutant tracing, YSI has developed the 6130 Rhodamine WT Sensor.
The 6130 is a fouling-resistant, wiped sensor designed to seamlessly integrate - using no external interface hardware - with all YSI sondes that contain an optical port. The YSI 6130 provides accurate, in situ measurement of Rhodamine WT in fresh, brackish, and sea water, as well as in stormwater and wastewater. The YSI 6130 Rhodamine WT Sensor rejects turbidity and chlorophyll interference.

The YSI 6136 Turbidity Probe is a fouling-resistant, wiped sensor designed to seamlessly integrate - using no external interface hardware - with all YSI sondes that contain an optical port. The YSI 6136 provides accurate, in situ measurement of turbidity in fresh, brackish, and sea water, as well as other applications requiring highly accurate turbidity data.

Copper-based parts on the YSI 6425AF Chlorophyll Sensor repel aquatic growth on sensors, extending deployment periods.
The probe is designed to estimate phytoplankton concentrations by detecting the fluorescence from chlorophyll in situ. The data can be useful in predicting detrimental algae blooms and, indirectly, in determining nutrient loading in environmental applications. The probe features a mechanical self-wiping capability for long-term monitoring.
The YSI 6425AF Chlorophyll Probe uses technology similar to that used by fluorometers, but the YSI sensor is much smaller, making it compatible with the probe ports in YSI's 6-Series instruments, including the YSI 6600 & 6600 V2 as well as the YSI 6820, 6820 V2, 6920, & 6920 V2. The YSI 6600 V2 sonde allows simultaneous measurement of four optical probes (dissolved oxygen, turbidity, chlorophyll, blue-green algae, and/or rhodamine), along with other parameters. The YSI 6820 V2 and 6920 V2 allow measurement of two optical probes, along with many other parameters.

Copper-based parts on the YSI 6431AF Blue-Green Algae Sensor repel aquatic growth on sensors, extending deployment periods.
Blue-green algae (a. k. a. cyanobacteria) monitoring is of growing interest due to the problems some species can present through the production of toxins and compounds that deteriorate the quality of drinking water and through the formation of blooms. Blue-green algae are of interest for ecosystem studies and monitoring as well, where they may represent the most abundant primary producer.

Copper-based parts on the YSI 6432AF Blue-Green Algae Sensor repel aquatic growth on sensors, extending deployment periods.
Blue-green algae (a. k. a. cyanobacteria) monitoring is of growing interest due to the problems some species can present through the production of toxins and compounds that deteriorate the quality of drinking water and through the formation of blooms. Blue-green algae are of interest for ecosystem studies and monitoring as well, where they may represent the most abundant primary producer.