Amperometric Chlorine Analyzer 

Model FX-CLv2 for Water That Fouls Sensor Membranes 



What It Does For You

The open cell bare electrode style FX-CLv2 amperometric chlorine analyzer gives you trouble free residual control and monitoring in virtually any water source, and excels in water that clogs chlorine sensor membranes, including wastewater.

Why Use Bare Electrodes?

Because high levels of iron, manganese, calcium or suspended solids clog the pores of chlorine sensor membranes, making them inaccurate and eventually inoperable.

Such misapplied sensors need continual cleaning and electrolyte replacement. In these cases what was intended or promised to be a low maintenance method turns out to be a higher maintenance alternative than our bare electrode analyzer.

Choose The Right Tool

There's a proper tool for every job, chlorine analysis is no different.

  • Use membrane chlorine sensors for clean water.
  • Use an open cell FX-CLv2 analyzer for dirtier water, simpler daily operation, or to avoid the complexity of maintaining, calibrating and replacing pH sensors used for compensation.

High Maintenance Is A Myth

Many assume the analyzer is high maintenance without considering the reality of its operation.

It only takes about an hour a year to install a preventive maintenance kit in drinking water analyzers, hardly high maintenance. You can spend more time troubleshooting, calibrating and maintaining the pH and chlorine sensors used in probe based analyzers.

The 24VDC pump and stirring motors run cool, so despite working 24 hours a day year in and year out, they still last at least 4 years.


Three configurations are available:

FX-CLv2: Uses ordinary food grade distilled white vinegar as a pH buffer (and cleaning agent) to measure free chlorine or total chlorine by adding potassium iodide (KI) to the vinegar. For any water source up to 10pH; excels in wastewater.

FX-CLv2-B: A bufferless model for clean water below 7.5pH

FX-CLv2-2CP: Includes a single two-channel buffer pump to feed a potassium iodide & distilled water solution separately from the vinegar. Recommended for total chlorine readings 10ppm or more, or to prolong the useful life of the KI solution.

Data loggers, circular chart recorders or remote monitoring systems can be provided with any of our analyzers. See the accessories page for more information.

Eco-Friendly & Proven Since 1980

The analyzer uses no toxic or costly reagents.

State of the art electronics have been added to the basic design that's worked over decades worldwide.

Simple design provides results with less time and effort.

Many of our customers have 10-20 year old instruments.


  • Distribution system monitoring.
  • Drinking water chlorination control
  • Wastewater disinfection and monitoring
  • Cooling towers
  • Food and beverage processing
  • NOT intended for dechlorination or to ensure the absence of chlorine

The Solution for This

If your water is doing this to your chlorine sensor membrane, sample lines and accessories then you're using the wrong tool to measure chlorine. It's like driving a family sedan off road in place of a 4-wheel drive utility vehicle.

With the FX-CLv2 you can eliminate frequent downtime and membrane cap cleaning with electrolyte replacement.

Extend the operational time between cleanings because the large bare electrodes and large internal ports are more tolerant of poor water quality.

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  • Easy trouble free operation
  • Accuracy of the amperometric method
  • Continuous auto electrode cleaning promotes stability
  • Variable speed buffer feed
  • Quick Clamp pump head
  • 4-20mA output of residual and temperature
  • 24VDC microprocessor electronics
  • Long lasting 24VDC stirring and pump motors
  • No flow sensor and programmable alarm relays.
  • Operating ranges from 0-1 ppm to 0-20 ppm are standard; high range chlorine up to 60ppm



Download  FX-CLv2 Brochure


Intuitive Touch Interface

"I didn't need the manual..."

Simplicity. There are no selection arrows to tap, no deep menus to navigate and buttons don't change their function in different screens.

Navigate by touching the words and enter your values on the screen generated keypad.

The 4.3" full color glass screen looks and reacts like your smart phone and is rated for 1 million touches on any one point.

It displays the residual, water temperature and alarm status. Sufficient flow is indicated by a blue water drop, and flow interruption by a red X.

The flashing "heartbeat" indicator in the lower left corner lets you know at a glance that the microprocessor is working.

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Panel Mount For Ease of Use and  Accuracy

Accurate readings begin with an accurate starting point, or zero point calibration. You're not monitoring bottled, distilled or de-ionized water on a continual  basis, so why use these as an artificial  zero point that will produce inaccurate results?

You need to factor out non-chlorine substances in your process water that generate a current that will be interpreted as being chlorine during operation. If not your readings will be higher than actual.

Panel mounting your analyzer gives you everything needed to calibrate and operate properly as well as making installation fast and easy.

The flow rotometer takes the guesswork out of setting a consistent and proper flow rate essential to amperometric chlorine analyzers. Pouring DI or distilled water from a container doesn't provide a proper or  consistent flow rate.

The included carbon filter removes chlorine from your process water when calibrating the zero point for more accurate readings. Simply use the selection valve to feed dechlorinated water when setting the zero point. When finished, flip the valve to feed chlorinated water for span calibration or normal operation.

Panel mounted systems are provided for Free Trial to ensure the analyzer is set up correctly to give you an objective test in your water system.

Simply provide a purchase order for a 30-day trial. Your only cost will be the shipping charge and return cost if you don't elect to keep the unit.

Request A Free Trial

Some of Our Satisfied Customers

City of Sugar Land, TX (about 30 systems)

City of Sparks, NV

City of Chillicothe, OH

Aqua PA Susquehanna Div.

Maine Water, various divisions

Town of Bennington, VT

Town of Durham, NH

City of Brooksville, FL

South Island PSD Hilton Head, SC


Some of Our Satisfied Customers

County of Maui, Wailuku, HI

City of Surprise, AZ

City of Kennewick, WA

City of Estherville, IA

City of Indio, CA

City of Deland, FL

City of Richmond, TX

City of Forsyth, GA

Orlando, FL


Some of Our Satisfied Customers

Sohar Intnl. Urea & Chemical Industries, Oman

City of Palm Coast, FL

City of Santa Paula, CA

City of Santa Cruz, CA

City of Sunrise, FL

Cedar Knox Rural Water, Hartington, NE

City of Gallup, NM

Georgetown County, SC

City of Breaux Bridge, LA

We had switched analyzers from a [popular DPD analyzer] years ago. The ease of use and maintenance was apparent from the start. The chemical costs to run this unit was an incredible savings. Also, the ease of ordering parts and getting help in answering questions was eye opening. Ray and the staff at Foxcroft are “ top of the line”. I truly cannot think of anything I would change about this unit. For us…. It was the way to go!
Daniel “Max” Driscoll, Chief Operator
Durham NH WWTP
We have these chlorine analyzers all over the city, they make my job a lot easier. (Note that Sugar Land Texas was runner up to a Canadian company in the AWWA 2019 best tasting water in North America competition)
Steve Jackson
City of Sugar Land, TX I&C Technician