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HOBO MX2501 - pH and Temperature Bluetooth Data Logger

Manufacturer:
The new low-cost HOBO® MX2501 pH and Temperature logger is designed for long-term monitoring of pH in estuaries, lakes, streams, rivers, and oceans.
Part Number: MX2501
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$1,424.00 ex GST
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Easy data offload to mobile devices via Bluetooth!

The HOBO MX2501 pH and Temperature Data Logger is designed for long-term monitoring of pH in estuaries, lakes, streams, rivers, and oceans. Leveraging Bluetooth Low Energy® (BLE) technology, the MX2501 pH Logger communicates wirelessly with the free HOBOconnect app and your mobile device or Windows computer, making logger setup, calibration, and data offload quick and easy. A guided pH calibration process on the HOBOconnect app makes an otherwise complicated process easier to follow. This affordable and compact logger dramatically cuts the time and effort needed to collect field data, while also offering higher resolution data. (NOTE: pH electrodes should always be stored in storage solution when not deployed.)



Highlighted Features

  • Guided pH calibration following on-screen prompts in HOBOmobile app
  • Rugged PVC housing for deployment in both freshwater and saltwater environments
  • Quick and easy data offload via Bluetooth Low Energy (BLE) to iOS devices
  • Water detection system for longer battery life and less maintenance
  • Potentiometric pH electrode with plastic body, gel electrolyte, and double cloth junction
  • User-replaceable battery, pH electrode, and anti-biofouling copper guard
  • Accuracy of ±0.10 pH units within ±10°C of temperature at calibration


Guided calibration on your mobile device

The HOBOmobile app's built-in guided calibration feature makes an otherwise difficult task a breeze, seamlessly walking you through the pH calibration process. 



In what environment does this data logger operate?

This data logger operates in an underwater environment.


What measurements does this data logger support?

The MX2501 data logger supports the following measurements: pH and Water Temperature


What's in the box?

  • MX2501 pH and Temperature Data Logger
  • pH electrode
  • Bottle of storage solution that can also be used as a storage container for the electrode
  • Anti-biofouling copper guard
  • Tube of silicone grease
  • AA battery


Important:

If you are purchasing the MX2501 for the first time you will also require the Calibration Kit.

Introducing - Onset HOBO pH and Temperature Data Logger

This video introduces the HOBO® MX2501 pH and Temperature Logger for long-term monitoring of pH in aquatic environments. The logger communicates wirelessly via Bluetooth Low Energy (BLE) to the HOBOmobile® app on a phone or tablet, making logger setup, calibration, and data offload quick and easy, with no need for extra equipment or complicated calibration procedures.


How to Replace the pH Electrode on the HOBO MX2501 pH Logger

This video provides guidance on the proper method for replacing the pH electrode in an Onset HOBO MX2501 pH and temperature logger.


How to Calibrate the HOBO MX2501 pH and Temperature Data Logger

This video will guide you on how to properly calibrate the HOBO MX2501 Bluetooth pH and Temperature logger. Calibration is important to compensate for tolerances due to manufacturing, as well as for electrode aging, conditioning, and cleaning. It is also used to confirm the condition of the electrode.


Webinar on Demand - HOBO pH and Temperature Loggers

This webinar reviews pH theory and introduces the HOBO® MX2501 pH and Temperature Logger for long-term monitoring of pH in aquatic environments. The logger communicates wirelessly via Bluetooth Low Energy (BLE) to the HOBOmobile® app on your phone or tablet, making logger setup, calibration, and data offload quick and easy, with no need for extra equipment or complicated calibration procedures.


Can I download data from an MX2501 pH logger deployed in water?

No, the logger needs to be removed from the water to download the data


Does the logger feature a user-replaceable electrode?

Yes


What type of pH electrode is used?

Plastic-bodied, double junction electrode with a Pellon junction and gel reference electrolyte


Can I calibrate with custom pH buffers?

No. The electrode is calibrated to 2 or 3 points using standard pH buffers (4, 7 and 10)


Is the calibration procedure the same for freshwater and saltwater applications?

The procedure itself is the same; however, some users deploying the loggers in saltwater may want to use a modified version of the pH buffers that includes chemicals (like Tris buffer) to make the hydrogen ion activity in the buffer more similar to its activity in saltwater.

The country of origin for this product is the United States. To see the full specifications for this product, please see our product manual found under the documentation above if available.

pH Sensor
  pH mV
Range 2.00 to 12.00 pH -512 to 512 mV
Accuracy ±0.10 pH units within ±10°C of temperature at calibration ±0.20 mV
Resolution 0.01 pH 0.02 mV
Response Time 1 minute typical to 90% at constant temperature in stirred water
Temperature Sensor
Range -2° to 50°C (28.4° to 122°F)
Accuracy ±0.2°C (±0.36°F)
Resolution 0.04°C (0.072°F)
Response Time 7 minutes typical to 90% in stirred water
Logger
Operating Range -2° to 50°C (28.4° to 122°F) — non-freezing
Buoyancy Fresh water: 13.6 g (0.48 oz) negative
Salt water: 19.6 g (0.69 oz) negative
Waterproof To 40 m (131.2 ft)
Water Detection Water conductivity level of 100 µS/cm or greater is necessary for reliable detection of water. Deionized water or water below 100 µS/cm may not be detected.
The water conductivity circuit may not reliably detect water that has frozen around the electrodes, i.e. below 0°C (32°F).
Radio Power 1 mW (0 dBm)
Transmission Range Approximately 30.5 m (100 ft) line-of-sight in air
Wireless Data Standard Bluetooth Low Energy (Bluetooth Smart)
Logging Rate 1 second to 18 hours
Logging Modes Fixed interval (normal, statistics) or burst
Memory Modes Wrap when full or stop when full
Start Modes Immediate, push button, date & time, or next interval
Stop Modes When memory is full, push button, date & time, or after a set logging period
Time Accuracy ±1 minute per month 0° to 50°C (32° to 122°F)
Battery Type One AA 1.5 Volt, user-replaceable
Battery Life 1 year typical at 25°C (77°F) with logging interval of 1 minute and Bluetooth Always On selected in software.
2 years typical at 25°C (77°F) with logging interval of 1 minute and Bluetooth Off Water Detect enabled in software.
3 years typical at 25°C (77°F) with logging interval of 1 minute and Bluetooth Always Off selected in software.
Faster logging intervals and statistics sampling intervals, burst logging, remaining connected with the app, excessive downloads, and paging may impact battery life.
pH Electrode Life 6 months
Memory 152 KB (43,300 measurements, maximum)
Full Memory Download Time Approximately 60 seconds; may take longer the farther the mobile device is from the logger
Dimensions 22.86 x 4.27 cm (9.0 x 1.68 inches)
Weight 268.2 g (9.46 oz)
Wetted Materials Logger: PVC housing and sensor end cap, polycarbonate closure caps and mounting end cap with a TPE switch
pH electrode: plastic-bodied with Pellon® junctions and gel electrolyte, glass pH sensor bulb
Environmental Rating IP68
CE Compliant The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).

Onset's HOBOconnect app, accessed from a free download from the iTunes or Google Play app store, or your pc, makes it quick and easy to configure compatible MX Series data loggers (chart below) and manage the collected data. From your mobile device, tablet, or Windows computer, users can view data in graphs, check the operational status of loggers, share data files and graph images for analysis in Excel, Numbers, and other applications, and store data in the cloud. HOBOconnect also makes it fast and easy to set up audible alarm notifications so users are immediately notified of problems.

  • Communicate to HOBO MX data loggers using Bluetooth (LE) technology
  • No internet connection required 
  • Set data logger's name, password, logging rate, alarm threshold, start and stop time
  • Automatically upload data to Onset's cloud-based HOBOlink software to store and merge data files
  • Configure and clear audible alarms
  • Page the data logger
  • Quickly download and view data
  • Export and share data as CSV, TXT, XLSX, or HOBO files





Download the free HOBOconnect app for your iOS or Android mobile device today. For documentation on the app, click here

  • Minimum System Requirements

    • iOS 11, 12 and 13
    • Android 7, 8, 9 and 10
    • Windows 10
    • Bluetooth 4.X and up

    Resources

Easy data offload to mobile devices via Bluetooth!

The HOBO MX2501 pH and Temperature Data Logger is designed for long-term monitoring of pH in estuaries, lakes, streams, rivers, and oceans. Leveraging Bluetooth Low Energy® (BLE) technology, the MX2501 pH Logger communicates wirelessly with the free HOBOconnect app and your mobile device or Windows computer, making logger setup, calibration, and data offload quick and easy. A guided pH calibration process on the HOBOconnect app makes an otherwise complicated process easier to follow. This affordable and compact logger dramatically cuts the time and effort needed to collect field data, while also offering higher resolution data. (NOTE: pH electrodes should always be stored in storage solution when not deployed.)



Highlighted Features

  • Guided pH calibration following on-screen prompts in HOBOmobile app
  • Rugged PVC housing for deployment in both freshwater and saltwater environments
  • Quick and easy data offload via Bluetooth Low Energy (BLE) to iOS devices
  • Water detection system for longer battery life and less maintenance
  • Potentiometric pH electrode with plastic body, gel electrolyte, and double cloth junction
  • User-replaceable battery, pH electrode, and anti-biofouling copper guard
  • Accuracy of ±0.10 pH units within ±10°C of temperature at calibration


Guided calibration on your mobile device

The HOBOmobile app's built-in guided calibration feature makes an otherwise difficult task a breeze, seamlessly walking you through the pH calibration process. 



In what environment does this data logger operate?

This data logger operates in an underwater environment.


What measurements does this data logger support?

The MX2501 data logger supports the following measurements: pH and Water Temperature


What's in the box?

  • MX2501 pH and Temperature Data Logger
  • pH electrode
  • Bottle of storage solution that can also be used as a storage container for the electrode
  • Anti-biofouling copper guard
  • Tube of silicone grease
  • AA battery


Important:

If you are purchasing the MX2501 for the first time you will also require the Calibration Kit.

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