understanding our quality Chlornie Sensor

When a shipping industry representative said to Halogen Systems President Michael Silveri that his lofty goals were an impossibility, Silveri only grew more determined. “He told me, ‘Big companies haven’t been able to do it.  We don’t really think you can do it,’” Silveri said. “Incidentally, they’re now a customer.”

DNV Type Approval

DNV GL is a globally leading quality assurance and risk management company. With 100,000 customers across the maritime, oil and gas, energy, as well as a range of other sectors, DNV GL helps companies to become safer, smarter and greener.

Supporting Innovation To Better Understand Global Waters

ACT is a partnership of research institutions, resource managers, and private sector companies dedicated to fostering the development and adoption of effective and reliable sensors and platforms for use in coastal, freshwater and ocean environments

Promoting Safe Ships and Clean Oceans

Boosting technologies related to ships, land & offshore facilities that enhance safety of life, property, and protecting the environment

Small Business Innovation Research Success Story

Through their small business solicitation they found a better solution for a critical issue: biofoul control.

Evironmental testing

In compliance with:

  • LR Rule
  • DNV 2.4
  • Tests included
  • Vibration
  • Susceptibility
  • EMI
  • Temp & Humidity Cycling


How long will the Halogen Systems Inc. Amperometric Chlorine Sensor last?
Our amperometric chlorine sensor should last the life of the system. No maintenance is usually necessary. In the event of abuse, the sensor may be reconditioned by simply repolishing it.

How often does our chlorine monitor measure?
The sensor measures five parameters: Chlorine, pH, ORP (oxidation reduction potential), Salinity, and Temperature every 50 seconds.

What are the scheduled maintenance requirements for the Chlorine Sensor?
We recommend a calibration check every 60 days and a pH calibration check every year. Recommended replacement of wear parts for the pH sensors is every two years.

Will the chlorine sensor work in freshwater?
Yes. It will measure accurately from 200 µS to fully marine seawater, typically 45 mS (34 PSU). It will likewise measure accurately in waters with a pH of 6.5 to 9.

Why does the chlorine sensor measure pH?
While the pH of seawater does not change much, in brackish or freshwater, the pH can change drastically from 6.5 to 9.0.

How is Halogen Stytems Inc. Fast Response ORP Different from typical discrete ORP?

Usually, the ORP measurement technique is different than a convention dedicated ORP unit. It could vary by as much as 50 mV but should provide qualitative readings comparable to a dedicated system. It is not subject to poisoning and will respond faster to changes in some cases.

How is Halogen’s pH sensor unique?

Halogen uses a unique pH cartridge in its sensor system. The pH cartridge can withstand 10 bar to -0.7 bar pressures and rapidly wets if allowed to dry out. Once reimmersed in water, the sensor’s accuracy restores in less than 3 minutes. Typically it does not require recalibration for a year or more, and the cartridge only needs replacing every two years.

Is the Amperometric Chlorine Sensor Type Approved?

Yes. ATEX/IECEx and the Non-Hazardous versions are both Type Approved by the Korean Registry of Shipping (KR).

comparison #1

DPD Online Instruments VS. the Halogen Systems Chlorine Sensor

Ballast Water Treatment Systems (BWTS) for larger ships use residual oxidant systems to inactivate invasive aquatic species. In both cases, the residual oxidant is bromine.

Sensors or analyzers are used in tandem to control the level of oxidant generated during ballasting by detecting the residual oxidant levels before deballasting (ballast water pumped out) operations occur. During ballasting, water is loaded, treated, and monitored to ensure the inactivation of invasive species is complete. During deballasting, sensors monitor the residual oxidant level to ensure that the residual concentration is below 0.2 (0.1 in some cases) ppm as required by International Maritime Organization and the US Coast Guard.

Most BWTS systems use N, N-diethyl-p-phenylenediamine, (DPD) Instrumentation at various locations onboard the ship. These units use regent feed colorimeters to indicate Total Oxidant levels. They require a relatively long cycle time of 75 seconds before displaying a reading. In addition to the cycle time, discarding the first or second measurement is typical due to initial inaccuracies. This delay gets compounded when the sample water must flow hundreds of feet to the colorimeter location before analysis can occur on larger ships. Sampling pumps, water lines, and automated valves are also necessary, increasing CAPEX costs.

While no analytical method is perfect, traditional DPD has several limitations in this application. They require:

  • Use of tubing as small as 1mm (ID) (which tends to clog via dried reagents or biofouling)
  • Filtration of the sample (Increase turbidity causes inaccuracies)
  • Filter cleaning
  • Cleaning of the colorimeter with acid every 60 days
  • Regent replacement every 60 days
  • Disposal of a waste stream

In general, these systems are complicated. They can be hard to troubleshoot and require considerable maintenance. For a limited-size crew, this can prove problematic as there are many duties during ballasting and deballasting.

Halogen Systems, Inc. manufactures Water Treatment sensors for Seawater, drinking water, swimming pools, and cooling towers. Its Oxidant/ Deoxidant Sensor for use in Ballast Water Treatment Systems is currently on-board ships. The sensor is installed directly in the ballast pipe and measures TRO every 50 seconds. These measurements are accurate within two and sometimes one cycle.

Halogen Systems’ Oxidant Sensor has some advantages in this application:

  • Long intervals between calibrations
  • Self-cleaning electrodes
  • Flow independent measurement
  • Direct pipe insertion
  • Integrated salinity measurement
  • Auto-ranging oxidant measurement from 0.07 ppm to 15 ppm
  • No electrolytes or membranes
  • Biofouling resistant

Halogen Systems chlorine sensor (TRO sensor) is just for this challenging application. It has a solution that can potentially save on both OPEX and CAPEX costs while simplifying operation by the ship’s crew.