Caldur® Chlorine HR (free + combined) – Photometric

CALDUR® Chlorine HR test set (free + combined) – Photometric

What is chlorine measured for in the High Range?

The CALDUR® Chlorine HR (High Range) test set is specially designed for applications where higher chlorine concentrations occur and precise photometric measurement is required. This is typically the case for shock chlorination in swimming pools, industrial disinfection processes, cooling water treatment or the treatment of heavily contaminated water. In these situations, the measuring range of standard chlorine tests is often not sufficient, which is why an extended measuring range of 1 to 10 mg/l Cl₂ is required.

Chlorine is the most commonly used disinfectant in the world for treating drinking water and swimming pool water. It reliably kills bacteria, viruses and other pathogens, thus ensuring hygienically safe water. In chlorination, a distinction is made between free chlorine and combined chlorine (chloramines), the sum of which is referred to as total chlorine.

Free chlorine is the active, disinfecting form and should be present in different concentrations depending on the application. Combined chlorine is produced by the reaction of free chlorine with nitrogen-containing compounds (e.g. urea, ammonia) and has a significantly lower disinfecting effect. In swimming pools, combined chlorine is responsible for the typical “chlorine smell” and eye irritation.

Typical applications for the high range:
– Shock chlorination in swimming pools (up to 10 mg/l)
– Industrial cooling water treatment
– Disinfection of waste water
– Treatment of well water with high microbial contamination
– Food industry (cleaning and disinfection)
– Laboratory analyses with the highest accuracy requirements

Regular measurement of both forms of chlorine is essential for effective disinfection while minimizing by-products. The CALDUR® Chlorine HR Test Set – Photometric enables the separate determination of free and combined chlorine in the extended concentration range with maximum precision by photometric evaluation.

How does the test set work?

The CALDUR® Chlorine HR Test Set – Photometric is based on the proven DPD method (N,N-diethyl-p-phenylenediamine). DPD reacts with free chlorine to form a pink-violet dye, the intensity of which is proportional to the chlorine concentration.

Measurement of free chlorine: After the addition of reagent A, a pink coloration corresponding to the free chlorine content develops immediately.

Measurement of combined chlorine: After adding reagent C, the combined chlorine is also measured. The difference between total chlorine and free chlorine gives the combined chlorine content.

The evaluation is carried out photometrically with the WINLAB Data Line photometer, which enables a much more accurate determination of the chlorine concentration than the visual color comparison. The DPD method is internationally recognized and complies with the standards DIN EN ISO 7393-2 and the recommendations of the WHO.

Advantages of the CALDUR® test set

• Quick analysis in just 1 minute

  Immediate results for free chlorine – ideal for daily routine checks

• Highest precision through photometric evaluation

  Objective measured values without subjective color interpretation – ideal for documentation and quality assurance

• Separate determination of free and combined chlorine

  Differentiated assessment of water quality and disinfection efficiency

• Extended measuring range 1 – 10 mg/l Cl₂

  Perfect for shock chlorination, industrial applications and higher concentrations

• 150 provisions per set – economical in continuous use

  Cost-effective for regular checks in swimming pools and industry

• DPD method according to international standards

  Standard-compliant according to DIN EN ISO 7393-2 – globally recognized reference method