Thermo Orion Star A321 Portable pH Meter
Features
- Calibration editing ensures accurate pH, mV, RmV and temperature readings
- AUTO-READ function alerts user and locks stable readings on backlit LCD screen
- USB and RS-232 ports allow easy data transfer of up to 5000 time-stamped data points
- Free ground shipping
- Expedited repair and warranty service
- Lifetime technical support
- More
Image | Part# | Product Description | Price | Stock | Order | |
---|---|---|---|---|---|---|
![]() | STARA3210 | Orion Star A321 pH Portable Meter | $837.00 | Drop Ships From Manufacturer | ||
![]() | STARA3215 | Orion Star A321 pH Portable Meter Kit | $1,439.64 | Drop Ships From Manufacturer |


Image | Part# | Product Description | Price | Stock | Order | |
---|---|---|---|---|---|---|
![]() | STARA-CS | Orion Star A-series portable hard field case | $158.10 | Drop Ships From Manufacturer | ||
![]() | 1210005 | Orion Star A-series portable soft field case | $165.54 | 1 Available | ||
![]() | STARA-AR | Orion Star A-series portable meter armor | $114.39 | Drop Ships From Manufacturer | ||
![]() | STARA-ESPH | Orion Star A-series pH electrode holder for use with armor | $31.90 | Drop Ships From Manufacturer | ||
![]() | 810017 | Orion storage sleeve & base for 12mm x 120mm electrodes | $61.85 | Drop Ships From Manufacturer | ||
![]() | 8107UWMMD | Orion ROSS Ultra pH/ATC Triode with epoxy body, low maintenance gel, waterproof BNC & MiniDIN connector, 3m cable | $586.83 | Drop Ships From Manufacturer | ||
![]() | 8107BNUMD | Orion ROSS Ultra pH/ATC Triode with epoxy body, low maintenance gel, waterproof BNC & MiniDIN connector, 1m cable | $607.29 | Drop Ships From Manufacturer | ||
![]() | 1010003 | Orion universal power adapter for Star meters | $74.31 | Drop Ships From Manufacturer | ||
![]() | 910410-WA | Orion pH 4 calibration buffer, (10) individual pouches | $39.15 | Drop Ships From Manufacturer | ||
![]() | 910710 | Orion pH 7 calibration buffer, (10) individual pouches | $39.15 | Drop Ships From Manufacturer | ||
![]() | 911010 | Orion pH 10 calibration buffer, (10) individual pouches | $39.15 | Drop Ships From Manufacturer | ||
![]() | 911110 | Orion electrode rinse, (10) individual pouches | $38.87 | Drop Ships From Manufacturer | ||
![]() | 9179BNMD | Orion ORP/ATC Triode with epoxy body, low maintenance gel, waterproof BNC & MiniDIN connector, 1m cable | $442.68 | Drop Ships From Manufacturer | ||
![]() | 967961 | Orion ORP standard, 60mL bottles, 5 pack | $102.30 | Drop Ships From Manufacturer |




The waterproof, battery-operated Thermo Orion Star A321 portable pH meter stands up to the most demanding field applications to deliver the most advanced performance of any portable meter. Four AA batteries, included with purchase of the A321, provide over 800 hours of continuous operation so the instrument is ready when it's needed, where it's needed. The meter displays reliable pH, mV, RmV and temperature readings on a large, backlit LCD screen and automatically locks in stable readings.
Thermo Orion Star A320 series portable meters provide the largest storage capacity available for time-stamped data points, which can be conveniently uploaded to a PC through the meter's USB and RS-232 ports. Automatic or 1 to 5 point manual calibration makes instrument setup simple, while icons provide quick updates on battery life, electrode status and calibration information. The simple button layout and on-screen messages also assist with calibration and explain setup menu choices.
- AUTO-READ function alerts user and locks on-screen readings when stable
- Up to 5 point pH calibration with calibration editing
- Automatic recognition of USA/NIST and DIN buffers
- Easy to recall calibration slope data for procedure checks
- Non-volatile memory holds up to 5000 data points
- USB and RS-232 ports to upload data and update included data analysis software
- Universal power supply or battery power option
- Includes (4) AA batteries to provide over 800 hours of operation
- Universal power adapter (sold separately) runs meter on AC power
- Multilanguage interface supports English, Spanish, French, Italian, German and Chinese
- IP67-rated waterproof housing (can be immersed up to one hour with no water incursion)
- 3 year meter warranty
- pH
- Range: -2.00 to 20.00
- Resolution: 0.1, 0.01, 0.001
- Relative Accuracy: +/-0.002
- Calibration Points: Up to 5
- Calibration Editing: Yes
- mV/RmV
- Range: +/-2000.0 mV
- Resolution: 0.1 mV
- Relative Accuracy: +/-0.2mV or 0.05%, whichever is greater
- EH ORP Mode: Yes
- Temperature
- Range: -5 to 105 C
- Resolution: 0.1
- Relative Accuracy: +/-0.1 C
- Offset Calibration: 1 point
- Datalogging
- Number of Points: 5000 with time and date stamp
- Log Function: Manual, ready (AUTO-READ), timed
- Log Edit: Delete individual points, group of points or all
- General
- Display: Backlit LCD
- Inputs: pH Electrode - BNC, ATC Probe - 8-pin mini-DIN
- Outputs: RS-232, USB
- Power Adapter: Universal AC, 100-240 VAC
- Battery Power: 4 AAs, 800 hrs life
- Environmental Requirements: 5 to 45 C and 5 to 85% relative humidity, non-condensing
- Regulatory and Safety: CE, TUV 3-1, FCC Class A
- IP Rating: IP67, waterproof
- Warranty: 36 months (from date of purchase)
Both meters have the same measuring ranges and feature an IP67-rated dust-proof and waterproof housing, The A321 features a 5000 point time/date stamped data log where the A221 features a 1000 point time/date stamped data log.
Yes, the calibration due alarm on the Star A321 can be set to a user-specified length of time.
In The News
Balancing Forest Biodiversity and Land Use Benefits
A new study by Fangyuan Hua, Assistant Professor at Peking University’s Institute of Ecology, compiles data showing that restoring native forests results in better biodiversity, greater carbon storage and more soil conservation and water provisioning benefits. However, the data also indicates that tree plantations are better at providing wood. 
 
The benefits and downsides of each forest type lead to tradeoffs in land management practices. In their paper , Hua and colleagues explore the advantages and disadvantages of different forest types, hoping to point the way toward better forest restoration practices. They hope to encourage practices that balance environmental goals with wood production needs.
Read MoreProtecting Endangered Species: Conducting Mussel Surveys
*This is part two of a two-part story on endangered mussels. To read part one, click here * 
With over 300 endangered mussel species in the United States, environmental agencies like EnviroScience rise to the challenge of protecting these vital species. When new construction sites are determined, the Endangered Species Act steps in to protect any endangered wildlife within the impacted area. Unfortunately, the protocols surrounding these protections can be complex and difficult to understand, making the work of scientists like Greg Zimmerman, Corporate Vice President for EnviroScience and an endangered mussel surveyor, vital to protecting biodiversity.
Read MoreProtecting Endangered Species: Why Freshwater Mussels Matter
*This is part one of a two-part story on endangered mussels. To read part two, click here * 
Though few people pay any mind to the occasional “clam” shell spotted along a river bank or lake, these small but mighty creatures are deeply important to water systems across the United States, and many of them are federally and state endangered. Greg Zimmerman of EnviroScience, Inc. shares, “We have about 300 species of mussels in the U.S., compared to other regions of the world like Europe that have under 20 species.” 
 
Zimmerman spent his life around water and always knew he wanted to return to help protect aquatic ecosystems. “I’ve always had a love of water, since I was 2. I grew up on an island in Buckeye Lake in Ohio.
Read More