Duo-ORpH Controller (Probe not Included)

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Captive Purity

Dual monitoring of pH and ORP with a large LED display and control of either pH or ORP. Highly accurate.

  1. Digital pH-ORP controller with large size LED display for easy reading.
  2. High input impedance avoid measuring error.
  3. Built in SLOPE and CALIBRATION adjustment knob, easy for single point or two points pH calibration.
  4. "ON - OFF" control, the relay "ON" when measuring value is above the set point for pH.
  5. And the relay "ON" when measuring value is below the set point for ORP.
  6. Front LED lamp indicate when relay "ON".
The Duo-OR pH Controller is probably the least expensive dual controller on the market today. But don`t be fooled by its price, it is extremely accurate. It does not have those bell & whistle features which you may not need, nor do you have to read a novel-thick of instruction booklet to study the Solar & Lunar phases. Its control is very straightforward. Buy either the pH or ORP probe (or both) for various applications.

With the electrodes in place, it can monitor both the pH and ORP readings at all times while controlling either the pH- or ORP-related devices. If one needs only a pH controller, just buy the pH electrode with the controller, and vice versa for the ORP application.

This spec. sheet tells you clearly why the controller is considered to be highly-accurate even to a professional (industrial) standard.

For Freshwater Aquarists - Get the Duo-ORPH Controller and a pH Electrode to control your CO2 System.
For Fish-Only Marine Aquarists - Get the Duo-ORPH Controller and both pH and ORP Electrodes to control your ozonizer and monitor your pH.
For Reef Aquarists - Get the Duo-ORPH Controller and both pH and ORP Electrodes to control your CO2-Ca Reactors and monitor your ORP.

General Specifications:
  pH ORP
Measurement 0 to 14 pH -1999 to 1999 mV
Resolution 0.01 pH 1 mV
Accuracy at 25 C ± (0.01 pH + 1 digit) after calibration ± (1 mV + 1 digit)
Impedance 1012 ohms 1012 ohms
Control Range 3.5 to 10.5 pH 0 to 1000 mV
Calibration Knob External pH 4 (SLOPE) pH 7 (CAL.)  

Relay Contact 10A for 125V AC 8A for 240V AC
Sampling Time 0.5 second
Display 0.5" LED, 3-1/2 digits
Operating Temperature 32 F to 122 F
Operating Humidity Max. 90% RH
Power Supply AC 110 V, ± 10%, 50/60 Hz
Power Consumption Approx. 2 watts
Dimension 5.9" x 3.4" x 1.6"
Weight 1.2 lb (incl. power cable)
pH Electrode BNC Connector
ORP Electrode BNC Connector

Note: Does not come with probes. Click here to see available probes.

Product Manuals & Documentation

Duo-ORpH Controller (Probe not Included)

Owner's Manual available for download in Adobe PDF file format

Manufacturer Info

Captive Purity manufactures water filtration and water testing supplies for marine and reef aquaria. The brand is best known for their high-quality line of reverse osmosis filter systems and accessories. Captive Purity also produces refractometers for testing salinity, portable pen-sized meters for testing pH as well as replacement filter media for their RO and RO/DI filter systems.



Experience Level: Intermediate

duo orp ph controller

Very simple to calibrate clean setup for controller power

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Experience Level: Expert

Great Customer Support

I've had the same controller for over 10 years and recently needed to replace the PH probe. When the new one arrived it lacked instruction on resetting the controller. Staff was great on troubleshooting the old controller and working with issues on the new probe.This is a great product and does the job without all the bells and whistles......I would recommend this probuct.

2 out of 2 found this review helpful

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Experience Level: Intermediate


The controller works great but the pinpoint orp probe does not work so I will have to return it this week.

3 out of 4 found this review helpful

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