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Residual Chlorine Monitor & Analyzer

Global Treat, Inc. continually strives to supply the most up to date user friendly water analysis instrumentation. This includes residual chlorine analyzers for municipal and industrial applications allowing for continuous online measurement and monitoring. These rapid response, high accuracy, total and free chlorine analyzers are designed for use in drinking water, industrial cooling and wastewater applications, in the range of 0-20ppm. Our chlorine analyzers utilize proven amperometric technology and are EPA approved for online residual monitoring in drinking water applications.

Global Treat, Inc. offers two different types of amperometric analyzers. Both types (the open flow cell #RAH-210 and the probe type #RPH-250) are available with temperature and pH compensation.

Series RAH-210: Open Flow Cell Chlorine Analyzer

The open flow cell Series RAH-210 is used for determining: Free Chlorine, Total Chlorine, Chlorine Dioxide, Bromine or Iodine in direct contact with sample water. The open flow cell style is the preferred chlorine monitor for wastewater applications due to its more forgiving mechanical design. The measurement cell consists of large copper and gold electrodes in direct contact with the sample water. This reagent-free analyzer for drinking water is continuous and does not rely on older colormetric "sample and hold" methods, similar to the Colormetric HACH Cl17, therefore, it provides a much improved process control. For Total Chlorine monitoring, food grade vinegar or acetic acid is used in combination with Potassium Iodide (KI), crystals as the buffer reagent.

Basic Specifications

Sample Water Flow 8 gal/hr
Sample Pressure 5 psig
Range 0 to 0.1 to 0 to 20mg/l (PPM)
Accuracy 0.003mg/l or +/- 1% of range, whichever is larger
Sensitivity 0.001 mg/l (1 ppb)


Main Features:

  • Measures Free or Total Chlorine
  • pH and Temperature Compensation
  • Optional pH probe compensation available
  • Continuous Chlorine measurement meter
  • Standard PID controller set point residual
  • Continuous sensor cleaning mechanism
  • Adjustable measurement range
  • Two 4-20mA outputs and one alarm relay
  • Alarm contact relay for signal loss
  • Optional data logger

Series RPH-250: Chlorine Probe Style Analyzer

The Series RPH-250 is an Amperometric Probe-Style Chlorine Residual Analyzer. This Bufferless Residual Monitor is also capable of controlling chemical disinfection feed systems. The chlorine probe style analyzer can be used for measuring Free and Total Chlorine and is a favorite for use in potable water applications. These reagent free chlorine analyzers are ideal for applications targeting water distribution networks, pumping stations, and other public drinking water facilities.

Basic Specifications

Sample Water Flow 8-26 gal/hr
Sample Pressure 15 psig
Accuracy 0.001mg/l or +/- 1% of range, whichever is larger
Sensitivity 0.01 mg/l (10 ppb)


Main Features:

  • Optional Data Logger
  • Measures Free or Total Chlorine
  • pH and Temperature Compensation
  • Transparent probe and inlet flow cells
  • Available Range: 0-2ppm, 0-5, or 0-10ppm
  • Allows simple calibration & maintenance
  • pH probe can be included
  • PRV, pressure gauge, sample control valve & meter tube provided
  • Cross-sensitive for: Chlorine Dioxide, Di & Tri-chloramine
  • Includes complete PID control programs
  • Provides two 4-20mA outputs & one alarm relay

Sample Water Recovery System

The Sample Water Recovery System is available as an accessory option for our Chlorine Analyzers. The purpose is to return sample water back to the process flow in order to eliminate wasting sample water.

Different Forms of Chlorine

Free Chlorine

Free chlorine is defined as the concentration of residual chlorine in water present as dissolved gas (Cl2), hypochlorous acid (HOCl), and/or hypochlorite ion (OCl-). A test kit which measures free chlorine will indicate the combined concentrations of HOCl, OCl-, and Cl2.

Combined Chlorine

Combined chlorine is defined as the residual chlorine existing in water in chemical combination with ammonia or organic amines which can be found in natural or polluted waters. Ammonia is sometimes deliberately added to chlorinated public water supplies to provide inorganic chloramines. This process is generally referred to as "chloramination."

Total Chlorine

Total chlorine is the sum of free and combined chlorine. When chlorinating most potable water supplies, total chlorine is essentially equal to free chlorine because the concentration of ammonia or organic nitrogen compounds (needed to form combined chlorine) will be very low.

When chloramines are present in a municipal water supply, total chlorine will be higher than free chlorine.

Make sure you're in compliance with the EPA's Final Ground Water Rule:
40 CFR ˜ Parts 9, 141 and 142 (Federal Register November 08, 2006)

The purpose of this rule is to reduce the incidence of disease. The EPA has established a risk-based guide that targets ground water systems with vulnerability to fecal contamination. Any ground water system that's in danger of fecal contamination should implement a corrective action for reducing potential illness from microbial pathogens. Global Treat, Inc. has more information regarding disinfection and treatment with chlorine plus equipment monitoring options to help ensure that you are complying with the new GWR rules.

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Total and Free Probe Style
Series RAH-210 Chlorine Analyzer
Series RPH-250 Probe Style Chlorine Analyzer
Sample Water Recovery System