STs Series™ pH Sensor
With over 40 years in the water quality business and customers like IBM, Siemens, and Lawrence-Livermore Berkeley Labs, pHionics has the experience and pH sensors you need to succeed.
Product Description
Most pH sensors fail—not because of faulty readings, but because one component wears out and the whole sensor gets tossed. Whether exposed to storms in the field or chemicals in wastewater, wear is inevitable. But with the STs Series pH Sensor, that doesn’t mean the end.
Every major component is modular and easily replaceable—without special tools—giving you an exceptionally long service life and lowering total cost of ownership.
It’s not just a sensor. It’s a smarter investment in uptime, reliability, and long-term performance. Build a more robust system with pHionics.
Check out the features, specifications, and product resources below and request a quote today.
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Quick Delivery!
Orders typically ship in 3-5 business days.
Have a question?
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Business hours:
9 am to 5 pm PST – Monday through Friday
Built-To-Last
With proper care, these sensors are designed for many years of reliable pH monitoring in harsh conditions. The truly unique aspect of the STs Series is that every part, including the cable, is easily replaceable in the event of wear/damage. This considerably extends their lifespan to save your company money. It also keeps waste out of landfills to support sustainable business practices.
Ground Loop Elimination
If you ever have a pH sensor sending erratic measurements and can’t figure out why, then there may be a “ground loop”. A ground loop occurs when the electrical circuit has multiple paths to ground that cause interference. This issue can be very difficult to detect and fix. The best way to avoid ground loops is with input/output electrical isolation, which is built into every pHionics sensor.
Low Maintenance
Very little is required to keep these sensors up. Just perform periodic calibrations and replace the electrode every few years*. Electrode replacement is a 60-second procedure that is easily performed in the field without any tools.
Full Features List
- 0-14 pH Range
- Combination double-junction electrode with large reference reservoir
- Built-in 0-50°C temperature sensor (2nd channel)
- Chemical-resistant PVDF and 316 Stainless Steel housing (Titanium optional)
- True 2-wire sensor for simple installation
- Solution ground
- Narrow diameter (0.75 inches or 1.9 cm)
- Removable electrode guard
- Fully submersible up to 70 psi
- Shielded, Kevlar®-reinforced, water-blocked polyurethane cable
- 4-20 mA signal capable of transmission up to 3 miles (with proper wire gauge)
- Automatic Temperature Compensation (2% per degree Celsius)
- Reversible Input Protection and Operation
- 2-second warm-up time
- Lowest power usage compared to other 4-20 mA pH sensors
- Isolated to prevent ground loops
- Signal conditioning to remove background noise
Specifications
pH Sensor
| Output | 4-20 mA |
| pH Range | 0-14 pH |
| Operational Temperature Range | 0-70°C |
| Electrode Type | Silver/silver chloride, double junction, replaceable gel electrode |
| Transmitter Type | 2-wire |
| Pressure Range | 0-70 psi |
| Automatic Temperature Compensation | 0-70°C |
| Isolation | 600 VDC |
| Power Supply Voltage | 8-40 VDC |
| Warm-up Time | 2 seconds |
| Response time | 95% < 5 seconds |
| Wetted Materials | 316 Stainless Steel, PVDF, Viton™, glass |
| Length | 14.25 in (36.20 cm) |
| Width | 0.750 in (1.9 cm) maximum |
| Weight (No cable) | 0.50 lbs (0.227 kg) |
| Linearity | ±0.014 pH* |
| Accuracy | ±0.014 pH* |
| Sensitivity | ±0.01 pH |
| Stability | ±0.03 pH per year |
| Repeatability | ±0.01 pH |
*After proper calibration
Temperature Sensor
| Output | 4-20 mA |
| Temperature Range | 0-50°C |
| Accuracy | +/- 1°C |
| Linearity | +/- 0.5°C |
| Power Supply Voltage | 7-40 VDC |
Cable
| Cable Material | Polyurethane |
| Type | 4 conductor, Kevlar® reinforced, water blocked, shielded, twisted-pair wiring |
| Maximum Distance | 3 miles |
| Resistance per 1000 ft (304.8 m) | 26 Ohms |
| Replaceable? | Yes |
pHionics products comply fully with all applicable EU Directives to bear the CE Mark.
Delrin® and Kevlar® are registered trademarks of DuPont™.
Viton™ is a trademark of Chemours.
Resources
Related Products
STs Series Conductivity Sensor
STs Series Dissolved Oxygen Sensor
