Besides a pressure and temperature sensor, the CTD-Diver has a four-electrode conductivity sensor for determining conductivity across a substantial measurement range (0-80 mS/cm). For each measurement, the date and time, groundwater level, temperature and conductivity are recorded. There are two options for conductivity measurement: display the measured conductivity or a specific conductivity at 77 °F. The CTD-Diver is accommodated in a ceramic casing which is resistant to corrosive conditions. The CTD-Diver has a memory with a maximum storage capacity of 48,000 measurement data per parameter.

 

Highlights

• Monitor conductivity, temperature, and water levels in corrosive waters
• Measure conductivity up to 120 mS/cm
• Monitor desalination, saltwater intrusion, brines, and wastewaters
• Memory capacity: 48000 measurements
• Battery life is capable of 2 million readings

 

Corrosion resistant multi-parameter groundwater datalogger

Professional applications of the CTD-Diver include:

• Aquifer storage and recovery projects
• Salinization projects
• Saltwater intrusion projects
• Discharge monitoring
• Monitoring landfill sites
• Monitoring groundwater and surface water
• Monitoring stored brines and reclaimed waste water

Groundwater quality recording

Frequent monitoring of soil and groundwater quality is traditionally a labour-intensive job. This is also the case if saltwater intrusion or contamination at remediation sites needs to be monitored.

The new CTD-Diver* by Schlumberger Water Services now sets the standard for reliability and longevity in groundwater quality monitoring. The CTD-Diver is a fully stand-alone datalogger with built-in non-volatile memory, battery and sensors. The compact ceramic casing and sensor and unparalleled conductivity measuring range (0-120 mS/cm) make the CTD-Diver suitable for use at every measuring site.

The CTD-Diver is impervious to the most aggressive substances found in water environments. Its ceramic casing resists when even the strongest metals yield.

CTD-Diver is a highly reliable, compact datalogger for the simultaneous measuring of groundwater level, temperature, and conductivity. These parameters are measured at time intervals pre-determined by the user. The measured values are stored in the datalogger’s non-volatile memory and can be read out at any given time.

CTD-Diver Benefits

• Frequent, long-term measuring without human intervention
• Reliable and accurate measurement data
• Easy calibration

Specifications

• Compact size, 18-22 mm [0.71 - 0.81 inch] diameter and 135 mm [5.3 inch] length for easy handling and installation
• Three sensors in one sealed, corrosion-resistant ceramic housing
• User-friendly software, including various export formats
• Battery life capable of 2 million readings

Programming

Programming the CTD-Diver takes only a few minutes on your computer in the field or at the office. You can enter location, instrument code, start date and time, sample rate, sample method, and select the conductivity range. If you select an event-based sample method, measured values are stored only if specified changed in conductivity occur. The CTD-Diver can start measuring at any time you specify.

Measuring

The CTD-Diver has three sensors: a pressure sensor to determine water level, a temperature sensor, and a four-electrode sensor to determine conductivity. The internal memory can store up to 48,000 measurements per parameter. For each measurement, the date, time, water level, temperature and (specific) conductivity are stored.

Reading Data

Data may be recovered using an optical reading unit; with the use of a Diver Data Cable (DDC) and a Pocket-PC or laptop you can readout the CTD-Diver without removing it from the monitoring well.

The CTD-Diver is supplied with the Diver-Office software package. Diver-Office is easy to use and offers additional features such as a barometric compensation wizard to convert pressure readings into water levels. Diver-Office also includes a calibration wizard for quick and easy conductivity sensor calibration. The data from the CTD-Diver is stored on your computer and can be exported in various formats to be used in a spreadsheet program or database.

Models

The CTD-Diver is available in three models with different pressure measuring ranges: (10, 50 and 100) meter water column. All models have a conductivity measuring range of 0–120 mS/cm and a ceramic casing which is practically damage- and corrosion-proof. The temperature range is from -20 °C to 80 °C.
  Frequently Asked Questions

 

Q: How do I install my Diver?

A1: Most Divers are installed underwater in a monitoring well. The depth at which you can suspend a Diver depends on the instrument’s measurement range. Determine the lowest possible water level measured from the top of the casing (or another reference point) prior to the installation. If the Diver is at least suspended at this depth, it is then certain that the Diver always measures the water level.

A2: The Diver can be suspended from a Diver Data Cable (DDC) or from a non-stretch steel cable by means of a suspension eye. Attach the Diver to the monitoring well cover and the suspension eye with two cable clips.

 

Q: How do I connect a Diver to my computer?

A: The way in which a Diver is connected to a computer depends on the way in which the Diver is installed in the monitoring well.

• A Diver hanging in the monitoring well suspended from a steel cable must first be removed from the monitoring well before it can be read out. The Diver is read out with the help of a PC, Pocket PC or a readout unit.
• A Diver suspended from a Diver Data Cable (DDC) can be left hanging in the well. This Diver can be read out with a PC or Pocket PC via a DDC interface cable.

 

Q: Is a Diver limited to being used at sea level?

A: No, Divers can be used from 300 m below sea level to 5,000 m above sea level.  

 

Q: Do you always need two Divers for measuring a single monitoring well?

A: No, but at least one Baro-Diver to monitor barometric pressure must be included in each network. For example, 20 Divers and one Baro-Diver would have to be installed for a network with 20 monitoring wells. We recommend installing one surplus Baro-Diver as a backup for larger networks. This is dependent on geographical conditions.  

 

Q: What is the radius from the Divers within which the Baro-Diver should be placed to ensure proper compensation for atmospheric pressure?

A: The rule of thumb on open terrain, at approximately the same level (above sea level), is one Baro-Diver within a maximum radius of 15 km.  

 

Q: What is the CTD-Diver’s battery’s lifespan?

A: The battery’s lifespan is dependent on the measurement frequency, number of data downloads, number of times of programming. The capacity is based on:

• 2 million measurements;
• 500 downloading a full memory;
• 500 times programming

Given past experience, a maximum lifespan of 10 years is considered standard under ‘typical’ use. Typical use means that, among other things, Divers are not exposed to extreme temperatures over extended periods of time, the measurement sampling interval is not set at 1 second, a download is not requested by modem every hour, etc.

Examples:

• 1 measurement per hour over a period of 10 years produces 87,600 measurements.
• 1 measurement every 15 minutes over a period of 10 years produces 350,400 measurements.

 

 

Q: How do I clean the Diver when it is very dirty?

A: If your Diver is very dirty, it can easily be cleaned with white distilled vinegar.

A diluted phosphoric acid solution may also be used for ceramic Diver types.

Place the Diver in the solution for some time. Always thoroughly rinse the Diver with clean water after cleaning, especially near the flow through openings. If necessary, use a soft cloth to remove any deposits. Never use any hard brushes, abrasives or sharp objects to clean your Diver.

 

 

Q: Must the Diver be calibrated?

A1: For the temperature and pressure this is not necessary. Schlumberger Water Services calibrates the Divers before they are delivered. A factory calibration certificate can be supplied as part of the production process.

The Divers can only be calibrated by Schlumberger Water Services. In case of doubt, the user can perform a control measurement locally.

A2: A field calibration can be carried out for the conductivity channel. See the Diver product manual and the Help of the software used (e.g. Diver-Office) for more information.

A general warning:

A conductivity calibration is a delicate matter. How the CTD-Diver is cleaned prior to the calibration, temperature-related matters and how the calibration liquid is handled are all very important. It is not recommended to calibrate the CTD-Diver in the field.

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