Seres OL

As of August 1, 2019, newly founded Seres OL is a part of the Swan. As a sub-supplier it provides niche parameters for industries and applications formerly not targeted by Swan Analytical Instruments.

With a new ownership and a new management, Seres OL will focus on the development and production of water and hydrocarbon analyzers of highest quality.

Online Water and Hydrocarbon Monitoring Excellence

As an experienced supplier of measuring products for the industrial online water monitoring, Seres OL provides its customers with modern, robust and low-maintenance analyzers and has been ISO 9001 certified since 2012.

Reliable Process Data, Sturdy Build

Analyzers of Seres OL pursue one goal only: deliver trustworthy data. Our robust, high performance instruments are optimized to persist in the field. Giving you correct information continuously and reflecting your actual water properties.

Globally Networked, Regionally Present

The range of products offered by Seres OL complements Swan Analytical Instruments. Together, the Swan group is your one stop shop for all online water monitoring equipment and turnkey sampling and analysis systems.

One Stop Provider Together with Swan

As part of the Swan group, Seres OL shares a collective sales, distribution and customer service network in over 65 countries. We are your global partner for quick and competent support with experts
on site.

Developed and Produced in Southern France

Lean structures characterize Seres OL. With all departments from R&D to production to quality control working closely together at our headquarters in Southern France, we take care of customer requests flexibly and in a straightforward manner.

Seres OL Product Range


TOC 0-2 ppm / 0-100 ppm and DOC

low maintenance, low reagent consumption, low operating cost

suitable for potable water measurements per EN DIN 1484

quick response time: 5-8 minutes per measurement

automatic zero-point detection


Detection of Oil in Water

reagent-free infrared nephelometer with automatic turbidity compensation

automatic mechanical cleaning of measuring chamber

available ex-proof (ATEX, IECEx, INMETRO, etc.)

available for marine applications (IMO resolution MEPC.107 (49) )


Detection of Water in Stored Oil

reagent-free capacitive probe

ex proof ATEX, IECEx, GOST, INMETRO, etc.

cost-efficient (capacity, material, disposal and man-hour savings)

easily installable without tank modification