NSF-61 Certified • Made in USAChlorine Analyzers & Sensors
A chlorine analyzer continuously measures free or total residual chlorine, the disinfectant, in drinking water and process water. It is not a chloride (salt) analyzer. Halogen makes the MP-5F for free chlorine, the MP-TOTAL for total chlorine and the MP-HOT for hot water.
Reagent-free, membrane-free amperometric technology with self-cleaning electrodes. NSF-61 certified for direct in-pipe installation. Deploy anywhere — wet-tap, immersion, side-stream, or flow cell.
Current Products & System Components
From single-parameter sensors to integrated cloud systems, Halogen offers solutions for municipal water systems, commercial buildings, maritime operations, and industrial facilities.
MP-5F Chlorine Sensor
Second-generation reagentless multiparameter free chlorine sensor with field-serviceable components and extended wear life. Reads zero chlorine indefinitely; self-cleaning lets it install in very dirty water.
MP-TOTAL
Free chlorine, monochloramine and total chlorine in one probe, for drinking water (works in wastewater too).
MP-HOT
Hot-water variants: confirm the qualified chemistry, operating limits and configuration for your application.
MP-ORP
Continuous pH and ORP measurement for process control, disinfection monitoring, and water treatment applications.
D20 Controller
Touchscreen display and control unit. 4-20mA output, Modbus, relay control.
Marine TRO Sensor
Ballast water TRO measurement — 5 parameters, no reagents, self-cleaning. DNV-GL, KR & IECEx certified.
Learn Morearrow_forwardHalogen Nexus
View sensor data history, trends, and real-time alerts with a Data Plan.
Learn Morearrow_forwardData from Anywhere
Cellular IoT, Sensus AMI, and BLE connectivity for remote monitoring.
Learn Morearrow_forwardHow chlorine analyzers measure
There are three ways online chlorine analyzers measure residual chlorine.
| Method | How it works |
|---|---|
| DPD colorimetric | Adds buffer and indicator reagents to a sample on a timed cycle and reads the color. Needs reagents, and the sample goes to a drain. |
| Membrane-covered amperometric | Measures the current from chlorine at an electrode behind a membrane. Reagent-free, with membrane and electrolyte upkeep. |
| Bare-electrode / in-pipe amperometric | Measures the current at exposed, self-cleaning electrodes. Reagent-free and membrane-free, and can install directly in the pipe. |
Chlorine analyzers by method
| Product | Measures | Method |
|---|---|---|
| Halogen MP-5F | Free chlorine | Reagent-free, membrane-free amperometric, in-pipe, SensiCLENE self-cleaning |
| Halogen MP-TOTAL | Total chlorine / monochloramine | Reagent-free three-electrode amperometric |
| Halogen MP-HOT | Free chlorine in hot water | Single in-pipe probe (free chlorine, pH, conductivity, temperature) |
| Hach CL17sc | Free or total chlorine | DPD colorimetric (reagents); Hach cites EPA 40 CFR 141.74 |
| Watts (HF scientific) CLX | Free or total chlorine | DPD colorimetric, Standard Method 4500-Cl G (buffer and DPD indicator reagents) |
| ABB ChloroStar (ACL420) | Free or total chlorine | Reagent-free, membrane-covered tri-electrode amperometric with built-in pH compensation |
| Yokogawa FC800D | Free chlorine | Reagent-free amperometric (polarographic) with rotating electrode and cleaning beads |
| Xylem (Wallace & Tiernan) SFC BA | Free or total chlorine | Reagent-free, membrane-covered amperometric sensor with buffered internal electrolyte |
| Hanna PCA300 series | Free or total chlorine | DPD colorimetric (indicator and buffer reagents), photometric |
Other makers' methods are from each maker's own product page, linked from the product name. This table compares measuring method and species only.
Choose a chlorine analyzer by application
Compare sensor families.
For a new free-chlorine project, start with MP-5F. For chloraminated water, review MP-TOTAL. Hot-water and marine applications require their own qualified configuration. Match the complete assembly—not just the probe—to the operating conditions.
| Family / status | Measurement | Operating conditions | Mounting | Power / interface | Documentation |
|---|---|---|---|---|---|
| MP-5F · current | Free chlorine, pH, ORP, conductivity, temperature | Free chlorine 0–10 mg/L; detection limit 0.03 mg/L; chlorine measurement pH 6.5–9.0. Confirm temperature and complete assembly limits. | Approved wet-tap, immersion, tee or side-stream assembly | 12–24 VDC; Modbus RTU. Review D20 or low-power/BTSB configuration. | MP-5F data sheet |
| MP-TOTAL · current | Total chlorine, monochloramine and free chlorine, with supporting water-quality parameters | Match residual species, range and water matrix to the current product specification. | Approved wet-tap, immersion, tee or M KIT | Review powered D20 or qualified battery/BTSB system; outputs depend on interface. | MP-TOTAL guide |
| MP-HOT · application review | Hot-water chlorine, pH, conductivity and temperature; confirm variant | Use the qualified hot-water model and its published temperature, pressure and chemistry limits. | Site-specific hot-water installation | Confirm controller, power and integration with the selected variant. | Hot-water specifications |
| Marine TRO · application review | Total residual oxidant in the specified marine configuration | Confirm oxidant, salinity, measuring range and applicable approvals. | Integration with the ballast-water treatment system | Confirm the OEM interface and complete system configuration. | Marine documents |
Analog 4–20 mA, relays and cellular reporting are system functions: select the required controller or adapter. A data plan is separate from sensor hardware. Compare connections →
Using MP5, MP5A, H2 or MP-Free documentation? Check the model-name reference →
Product previews and release status
MP7 and TURB Series are coming soon. The MP-5T name has been retired; total chlorine and monochloramine projects use the MP-TOTAL. Current projects can be reviewed against MP-5F and MP-TOTAL.
Installation Options
Deploy your sensor in the way that fits your infrastructure. Wet-tap into a main line, immerse in a tank, install in a vault, or use a side-stream flow cell.
Ballast Water Compliance
Total Residual Oxidant (TRO) monitoring for international maritime ballast water management regulations. Real-time compliance reporting and remote telemetry for fleet vessels.
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Chlorine analyzer FAQ
Is a chlorine analyzer the same as a chloride analyzer?
No. A chlorine analyzer measures residual chlorine, the disinfectant added to drinking water and process water, as free or total chlorine. A chloride analyzer measures chloride, the salt ion, which does not disinfect. If you need to confirm disinfection in a water system, you want a chlorine analyzer.
What is the difference between free and total chlorine?
Free chlorine is the chlorine available to disinfect, as hypochlorous acid and hypochlorite. Total chlorine is free chlorine plus combined chlorine such as monochloramine. Systems that disinfect with chlorine measure free chlorine; chloraminated systems measure total chlorine or monochloramine, for example with the Halogen MP-TOTAL.
Which chlorine analyzers do not need reagents?
Amperometric analyzers are reagent-free. That includes the Halogen MP-5F, MP-TOTAL and MP-HOT, plus membrane-covered amperometric units such as ABB ChloroStar, Yokogawa FC800D and Xylem SFC BA. DPD colorimetric analyzers, such as the Hach CL17sc, Watts CLX and Hanna PCA300, use buffer and indicator reagents and send the sample to a drain.
Do Halogen chlorine analyzers meet EPA Method 334.0?
Yes. The Halogen MP-5F free chlorine sensor is EPA Method 334.0 compliant for regulatory reporting. Method 334.0 covers on-line residual chlorine analyzers in drinking water and does not require one technology. Your state primacy agency decides which methods it accepts, so confirm with it before changing your online method of record.
Not sure which sensor you need?
Answer a few quick questions about your water system, application, and requirements. Our Product Selector recommends the ideal Halogen configuration for your site.
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