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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

Calibration Kit

Include MX2500 Calibration Kit [+$151.00]

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$1,877.00 ex GST

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Overview
Video Library
FAQ
Specification
HOBOconnect

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 HOBOconnect 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 HOBOconnect 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

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 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.

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.

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.

Technical Information
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
Sample Ionic Strength	≥ 100 µS/cm
Temperature Sensor
Range	-2° to 50°C (28.4° to 122°F)
Accuracy	±0.2°C (±0.36°F)
Resolution	0.024°C at 25°C (0.04°F at 77°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 Typical Minimum Life	6 months in sample with ionic strength ≥ 100 µS/cm
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); mounting hole 0.64 cm (0.25 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	The CE Marking identifies this product as complying with all relevant directives in the European Union (EU).

Download the free HOBOconnect app for your iOS or Android mobile device or Windows computer today.

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.

For documentation on the app, click here >>

Learn more about HOBOconnect >>

Easy data offload to mobile devices via Bluetooth!

Highlighted Features

Guided pH calibration following on-screen prompts in HOBOconnect 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 HOBOconnect 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

Important:

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

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HOBO MX2501 - pH and Temperature Bluetooth Data Logger

Easy data offload to mobile devices via Bluetooth!

Highlighted Features

Guided calibration on your mobile device

In what environment does this data logger operate?

What measurements does this data logger support?

Important:

Introducing - Onset HOBO pH and Temperature Data Logger

How to Calibrate the HOBO MX2501 pH and Temperature Data Logger

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

Webinar on Demand - HOBO pH and Temperature Loggers

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

Does the logger feature a user-replaceable electrode?

What type of pH electrode is used?

Can I calibrate with custom pH buffers?

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

Technical Information

pH Sensor

Temperature Sensor

Logger

Download the free HOBOconnect app for your iOS or Android mobile device or Windows computer today.

iOS App Download

Android App Download

Windows Download

Learn more about HOBOconnect >>

Easy data offload to mobile devices via Bluetooth!

Highlighted Features

Guided calibration on your mobile device

In what environment does this data logger operate?

What measurements does this data logger support?

Important:

HOBO - Replacement DO Sensor Cap

HOBO MX2203 TidbiT - Water Temperature 400' Bluetooth Data Logger

HOBO U26 - Dissolved Oxygen Data Logger

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