Track Conductivity, Dissolved Oxygen and more!
For more than 25 years, Onset’s HOBO data loggers have set the standard for reliable, and accurate water quality monitoring.
- Quick and simple deployment
- Rugged design for harsh environments
- Easy setup and analysis with HOBO software
- Models available for easy, wireless data offload with mobile device

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The HOBO MX2203 TidbiT waterproof temperature logger leverages the power of Bluetooth Low Energy (BLE) to deliver high-accuracy temperature measurements straight to your iOS or Android mobile device. Designed for durability, this rugged waterproof logger is ideal for long-term deployments in streams, lakes, and oceans (up to 400 foot depths). Data collection in the field has never been easier!
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The HOBO U20L-002 is a low-cost, research-grade water level data logger for continuously measuring water level and temperature in a wide range of underwater environments. It features 0.1% accuracy, a polypropylene housing for use in both fresh and salt water, and a non-vented design for convenient and hassle-free deployment.
Helpful Links:
Barometric Pressure Compensation Assistant Demo
Multi-rate Sampling Demo -
Measure oxygen concentrations in lakes, streams, rivers, estuaries, and coastal waters with the HOBO U26 Dissolved Oxygen Data Logger. This affordable and precise data logger is recommended for aquatic biology and hydrology research projects. The HOBO U26 uses RDO® Basic (Rugged Dissolved Oxygen) optical DO sensor technology and is easy to maintain.
Includes:
- U26-001 data logger
- DO sensor cap
- Protective Guard
- Calibration Boot with sponge
Our HOBO U26 Dissolved Oxygen logger has been part of a multi-year evaluation of DO loggers and sensors by the Alliance for Coastal Technologies (ACT), and the results have just been published online. This provides an un-biased report of how our U26 performs in lab and field conditions. Note that our response letter with our added recommendations is attached at the end of this report on pages 58 and 59.
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This high-accuracy conductivity data logger is a cost-effective way to collect water quality data. The HOBO U24 measures and records both conductivity and temperatures in streams, lakes, and other freshwater sources. This logger is recommended for monitoring aquifers for saltwater intrusion and road and agricultural runoff. This product’s open access to its sensor simplifies cleaning and maintenance. The HOBO U24’s non-contact sensor minimizes measurement errors related to drift. In addition, the logger features software-based drift compensation.
The HOBO U24 Conductivity data logger features a non-contact sensor with a Titanium Pentoxide coating. This coating prevents the sensor from coming in contact with the water, which in turn prevents tarnishing or corrosion associated with traditional electrode sensors. This sensor coating is also inert, enabling fouling to be easily wiped off the sensor.