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pH/ORP: Monitor/Controllers, pH 721-724, ORP 756-759

pH/ORP: Monitor/Controllers, pH 721-724, ORP 756-759


  • Affordable
  • Ease of Operation
  • Low Maintenance
  • Ensures Product Quality

The advanced "isolated" circuitry of the 720 Series II pH/ORP Monitor/controllers guarantees accurate and reliable measurements completely eliminating ground-loop and noise issues.

The unique sensor preamp allows for longer distances between the sensor and the Monitor/controller without the loss of accuracy or reliability.

All Myron L® Monitor/controllers feature a highly refined and precise Temperature Compensation circuit. This feature perfectly matches the NERNST equation correcting the displayed reading to 25°C. The TC may be disabled to conform with USP requirements.

Built-in electronic calibration allows for fast quality checks without buffers.
(Note: for maximum system accuracy buffers are recommended).

A push-to-test button makes set point checks easy, while the internal alarm set discourages unauthorized adjustments.

Standard on all controller models is a heavy-duty 10 amp output relay, operating on either increasing or decreasing readings. Bright green/red LEDs indicate above/below set point readings.

All 720 Series II models feature an IP65/ NEMA 4X water resistant and corrosion proof rated enclosure.
Compact in size, at 152 x 122 mm/6 x 4.8 in., the 720 Series II models are suitable for panel, bench or surface mounting.

Additional options include a Remote Alarm™ model RA.


  • Process Control
  • Reverse Osmosis
  • Seawater Desalination
  • Waste Treatment
  • Food Processing
  • Plating
  • Power Plants
  • Laboratories
  • Printing
  • Paper & Pulp
  • Boilers & Cooling Towers
  • Potable Water
  • Waste Water Treatment
  • Swimming Pools & Spas
  • Bleach Manufacturing
  • Reduction of Chromate Waste
  • Environmental


  • pH 0-14 or ORP ± 2000 mV
  • Choice of 3½ digit display or analog meter
  • Advanced "Isolated" circuitry
  • Automatic temperature compensation to 25°C (NERNST equation)
  • Isolated 0-10 VDC Recorder Output standard
  • IP65/NEMA 4X water resistant and corrosion-proof enclosure
  • Built-in electronic calibration
  • Single set point/alarm standard
  • Adjustable set point hysteresis
  • Solid State 24 VDC Output
  • 10 amp relay operates on choice of increasing or decreasing reading
  • Push-to-test set point check
  • Internal set point discourages unauthorized adjustment
  • Selectable 115/230 VAC
  • Unique, easily installed sensors
  • CE Certified
  • Unique, easily installed sensors
  • Heavy duty "F" model sensors may be installed in ANY direction including inverted


These highly accurate sensors utilize a preamplifier to ensure stability over longer distances, and to eliminate potential noise problems thereby ensuring accurate repeatable readings.

In addition, these reliable sensors feature an integral temperature sensor to ensure accurate and rapid automatic temperature compensation.

Several choices of sensors are available, in 1/2" MNPT or 3/4" MNPT, depending on the demands of the application. The basic pH sensor utilizes the standard round glass electrode with a single reference junction. The basic ORP sensor utilizes a Platinum electrode with a single reference junction. See 720II Sensor Selection Guide for additional information.

NOTE: Heavy Duty "F" model sensors may be installed in ANY direction including inverted.


  • Temperature Compensation: Integral temperature sensor provides automatic TC to 25°C between 0 - 100°C/ 32 - 212°F.
  • Pressure/Temperature Limits: P72S: Intermittent use up to 50 psi/690 kPa 100°C/212°F. High Temperature models available, see pH/ORP Sensor Selection Guide.
  • Cable: 5 wire, 24 ga. shielded, 10 ft./3 meters standard. 25 and 100 ft./8 and 30 meter lengths available.
  • Material: 1/2" MNPT: CPVC body. 3/4" MNPT: Ryton®** body.
  • Dimensions: P72S typical: overall length 165 mm/6.5 in., body 127 mm/5 in., electrode length 19 mm/.75 in.

**Ryton® PPS is a registered trademark of Chevron Phillips Chemical Company LLC

Limited Warranty
All Myron L® Monitor/controllers have a Two (2) Year Limited Warranty. pH Sensors have a Six (6) Month Limited Warranty. If any Monitor/controller fails to function normally, return the unit to the factory prepaid. If, in the opinion of the factory, failure was due to materials or workmanship, repair or replacement will be made without charge.
A reasonable service charge will be made for diagnosis or repairs due to normal wear, abuse or tampering. Warranty is limited to the repair or replacement of Monitor/controller only. The Myron L® Company assumes no other responsibility or liability.

pH Sensors and ORP/Redox Sensors Notes:
* Intermittent use up to 100°C @ 50 psi.
Maximum recommended continuous use 100°C @ 50 psi, 81°C @ 85 psi, and 76°C @ 100 psi.

  • Models: 721II, 722II, 723II, 724II, 726II, 727II, 728II, 729II, -SC, -4A, -PA, -PAT, -35BL, -TP, -TH, -PC, -24VA, -PTS, -SFP, -TPA, SCO, 4AO, 3SE, 3SO, PAO, PATO, 35BLO, TPO, THO, TPC, PCO, SMP50, RA, VR, 024-1, PHC, PHCS, OC, P72S, P72D, P72LC, P72F, P74SR, P74DR, P74LCR, P74FR, O72S, O72D, O72LC, O72F, O74SR, O74DR, O74LCR, O74FR, -25, -100, -HT, -SQC & ITS1

Please Choose:
Check the box for the product, then add to the cart.

pH (Myron L® pH Sensor required)

ORP/Redox (Myron L® ORP Sensor required)

pH and ORP Options

pH and ORP Special Order Options

pH and ORP Accessories

NIST Certifications

pH Sensors

ORP/Redox Sensors

pH and ORP Sensor Options

pH and ORP Special Order Sensors

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**Prices, images and specifications subject to change without notice.**

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