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Xylem Analytics


Xylem Analytics (YSI Hydrodata), based in Letchworth Hertfordshire, market a comprehensive range of instruments for monitoring water quality either on-line, in the field or in the laboratory, and the company's parent (YSI) is the world's leading manufacturer of instruments for monitoring the quality of natural water in rivers, streams, lakes, reservoirs, underground and coastal applications.


Mr Darren Hanson
Unit 2 Focal Point Lacerta Court
Works Road

New Generation of Multiparameter Water Quality Monitors

To accommodate twice as many optical sensors as well as provide mechanical improvements, YSI has released new versions of its multiparameter water quality instruments, called sondes. The "version 2" (V2) features add up to a multiparameter sonde with the industry's most versatile and complete sensor payload that can tolerate the most severe environmental conditions. YSI's V2 sonde launch coincides with the launch of its ROX Reliable Oxygen Sensor and two versions of its Blue-green Algae Sensor (freshwater and marine).

A quick return to YSI Hydrodata will easily convert existing 6820, 6920, or 6600 sondes into V2 sondes for YSI customers. The first upgrades available are for the 6820 and 6920. These instruments measure up to 16 parameters simultaneously; the 6920 can run on batteries and log data. Both are suited for profiling or sampling in fresh, sea, or polluted waters.

A typical YSI 6-Series sonde, after a simple upgrade, can measure optical dissolved oxygen, blue-green algae, turbidity, chlorophyll, temperature, depth, conductivity, and pH.

For harsh fouling environments, YSI's next generation optical sensors - dissolved oxygen and blue-green algae - feature an integrated wiper that prevents the impacts of biofouling, a corrosion-resistant titanium wiper shaft, and replaceable seals.

New fluorescence sensors from YSI detect pigments specific to blue-green algae (cyanobacteria). The monitoring of blue-green algae is of growing interest due to the problems some species can present through the production of toxins and compounds that deteriorate the quality of 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 producers in some environments. This is often the case in open ocean environments due to their efficiency in low nutrient conditions.

YSI's blue-green algae sensors optimise the limit of detection to allow monitoring of natural concentrations, typically low, of blue-green algae and identify when biomass is on the rise. An increase in biomass, generally associated with other changes in water quality parameters, can be indicative of a bloom and allow researchers or managers to take action before potentially dangerous conditions occur.

These two sensors use the in vivo fluorometry (IVF) technique, which measures the fluorescence of accessory pigments unique to blue-green algae: phycocyanin or phycoerythrin. Because there is no special sample handling or processing required, IVF is ideal for profiling, moored, and real-time data collection using YSI multiparameter sondes.

Multiple Options Available for Real-World Applications

Phycocyanin Blue-Green Algae Sensor (BGA-PC)
The BGA-PC sensor is designed for freshwater and estuarine conditions. Common applications in these environments include:

· Monitoring taste- and odour-causing species in drinking water reservoirs

· Detecting the presence of potentially harmful or toxic species as part of Harmful Algal Bloom monitoring systems

· Monitoring in agriculture ponds where blue-green algae can potentially harm livestock

· Ecosystem monitoring research where BGA impact primary productions and nutrient cycling

Phycoerythrin Blue-Green Algae Sensor (BGA-PE)

The BGA-PE sensor is designed for marine and estuarine conditions. Common applications in these environments include:

· Ecosystem monitoring research where microalgae represent important primary producers and impact carbon and nutrient cycling

· As a key sensor in a Harmful Algal Bloom monitoring system for long-term monitoring in sensitive coastal environments

· Monitoring in or around aquaculture facilities where BGA can potentially harm marine stocks.

A luminescence-based dissolved oxygen sensor from YSI offers researchers and water quality technicians a powerful tool for making long-term oxygen measurements in severe fouling and low-oxygen environments. A rugged design and large measurement range (0 to 50 mg/L) are key features for deployed, spot sampling, flow cell, and groundwater measurements.

The optical sensing system of the YSI ROX (Reliable Oxygen) sensor is based on the luminescence lifetime method. This offers the most stable, repeatable, and sensitive method for dissolved oxygen calculation, thus reducing sensor drift and prolonging deployment times.

YSI Regional Manager Ian Thompson comments "Our employee-owners work alongside customers in the field and understand first-hand what works well. The insight we have gained has been transferred into the design of the new ROX sensor."

Widest Detection Range Available

The YSI ROX has the widest detection range of any optical DO sensor available: 0 to 50 mg/l or 0-500% saturation. This matches all data from the proven YSI 6-series Rapid Pulse" polarographic sensor.

ROX's optical measurement method does not require stirring. Additionally, the ROX membrane differs from the traditional electrochemical sensor membrane, requiring fewer steps for installation and less maintenance. ROX membranes will last for one year and are made of a durable material that is unlikely to be damaged in the field.

For harsh fouling environments, ROX features an integrated wiper that prevents the impacts of biofouling and a corrosion-resistant titanium wiper shaft.

Commenting on the launch of the V2, YSI Regional Manager Darren Hanson says "YSI understands the challenges facing field scientists and technicians. All our sensors are field replaceable and perform extremely reliably for long deployments. Our upgraded instruments will provide them with the quality data they need at a total cost of ownership they can afford."

Throughout 2006 YSI will continue to release upgraded versions of other multiparameter sondes in its 6-Series line.

For further information please email YSI Hydrodata Ltd

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