pHionics STs Series ORP Water Quality Sensor

Accurate and low-maintenance operation is ensured with noise-resistant 4-20 mA analog signals and a large-volume, double-junction electrode.  Typical electrode life is 2-4 years and, when needed, a replacement is easily installed thanks to pHionics’ patented pHiConn™ Connector System.  

In addition, the electronics are isolated to prevent ground loops and proprietary signal conditioning virtually eliminates background noise. 

Durability is guaranteed with chemical-resistant 316 Stainless Steel (titanium optional) and high-quality double O-ring seals that last many years, even in harsh conditions.  

When combined with the compact design (0.75 in. or 19 mm diameter), this ORP sensor proves to be compatible with a wide range of applications including aquaculture, environmental monitoring, and pollution control.

If you need a sensor that works anytime, anywhere, for many years, then the pHionics STs Series ORP sensor is here for you. 

Ranges available

• -1000 to +1000 mV
• -1000 to +0 mV
• -500 to +500 mV
•  +0 to +1000 mV

Key Features

• Replaceable electrode with platinum sensing element measuring -1000 to +1000 mV oxidation-reduction potential (ORP). ORP is also referred to as redox potential or EH
• Large, gel-filled reference to reduce calibration frequency
• Secondary 0-50°C temperature sensor 
• 4-20 mA signal capable of transmission up to 3 miles (with proper wire gauge) 
• Isolated to prevent ground loops 
• Chemical-resistant Delrin®, PVDF, and 316 Stainless Steel housing (Titanium optional) 
• Narrow diameter (0.75 inches or 1.9 cm) 
• Removable electrode guard to reduce debris or algae buildup and protect from damage 
• Fully submersible up to 70 psi 
• Shielded, Kevlar®-reinforced, water-blocked polyurethane cable 
• Reversible Input Protection and Operation
• 2-second warm-up time and low power usage to avoid battery drain of datalogger or RTU
• Signal conditioning to remove background noise .

Low Maintenance

The weak point of ORP sensors is their reference solution, which gets diluted by the sample over time.  STs Series ORP sensors mitigate this problem by incorporating a reference half cell with a large reservoir.  The high volume, combined with a low-flow reference gel and junction, reduces the dilution rate to provide stable measurements with less calibration.