The data on the left is from a traditional Clark-electrode, while the one on the right is from an RDO sensor. Surprisingly, this data is from the same sample. So why the difference? The truth is that so many factors can influence the readings of a Clark-electrode and without good experience, it is had to get good data. Optical D.O. can obtain the correct the results without all the hassle.

Features:

• High precision and accuracy. Measure absolute oxygen concentrations without field calibrations
• Integrates directly into the TROLL 9000 with Smart Sensor technology - "Plug & Play"
• No membrane required
• No stirring/flow required
• No anode or cathode to scrub or clean.
• No membranes / No electrolyte
• 5 years / 5 Million readings before lumiphore is exhausted
• Up to 1 year between calibrations
• Minimal maintenance / no hazardous cleaning solutions
• No flow requirements
• Fast and stable response
• Low drift
• Excellent performance in anoxic conditions (0 ppm)
• Not "poisoned" by Sulfides
• Not subject to "thermal shocking"
• No cross sensitivity to: H2S, pH, CO2, NH3, SO4-, Cl-, Cl2, ClO2, MeOH, EtOH, various ionic species

Rugged Construction with Flexible Installation
The powerful Rugged Dissolved Oxygen sensor ("RDO") with optical technology means peace of mind with dissolved oxygen monitoring. It is available as an optional sensor that plugs right into new and existing TROLL 9000s. The design makes it easy to add or remove and can be used any time you require high quality D.O. readings without the hassle.

Dissolved Oxygen (DO) is one of the single most important parameters monitored when examining aquatic biology and related processes. Until recently the ability to accurately monitor dissolved oxygen levels over long periods of time was limited. Existing electrochemical sensors (Clark, Galvanic) require sample stirring and are functionally limited by the durability of their membrane and electrode, while galvanic diffusion types offer characteristically slow response. The new RDO sensor provides superior performance to traditional DO sensing technology currently on the market.

The micro-optical technology incorporated in the RDO sensor centers around the extensively field-proven methodology of Lifetime-based Luminescent Dissolved Oxygen detection. This solid-state method uses LEDs to excite a fluorescent material, while an optical receptor gauges the duration, or lifetime, of the event. The duration of fluorescence is inversely proportional to the ambient amount of dissolved oxygen in the water.

Environmental Industry interest in the RDO sensor is centered around the fact that in many instances it can remain deployed through entire testing seasons - spanning months without calibration; at the same time retaining its accuracy in even the harshest of fouling environments, without the need for stirring.

All dissolved oxygen sensors are affected by active bio-fouling. Optical D.O. technology is also affected by fouling in the sense that the actual D.O. levels may be increased or decreased around the sensing element. However, the difference is that an optical D.O. sensor can simply be cleaned and redeployed with NO need for recalibration.

When viewed from the bottom line, benefits of this sensor are not only the time/money saved with freedom from calibration, but also notably reliable and accurate test data.

Successfully tested and deployed over 300 sensors in the following environments:

Harsh environments:

• Fresh water applications
• Brackish water
• Dirty water
• Ground-water
• Waste streams

Oceanic application:

Depths of up to 6000 meters
• High salinity
• Low temperature
• Long-term deployment (greater than 6 months)