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Free Chlorine Medium Range Test Kit - HI3875


In stock

The HI3875 is a chemical test kit that uses the DPD method to measure free chlorine between 0 and 3.5 mg/L. The HI3875 is supplied complete with all of the reagents and equipment necessary to perform approximately 100 tests.

  • Pre-made reagents for ease of use
  • All reagents marked with expiration date and lot number for traceability
  • Checker® disc for more accurate determination


The HI3875 is a chemical test kit that determines the free chlorine concentration within a 0.0 to 3.5 mg/L (ppm) range. The HI3875 is supplied with all of the necessary reagents and equipment to perform the analysis, including the Checker® disc for accurate determination. The test kit contains enough reagents for perform approximately 100 tests.

Features at-a-glance

Complete setup

  • All required materials are included with the test kit, such as the glass vials, plastic pipette, reagent packets, and Checker® disc.

High resolution

  • Readings from 0.0 to 3.5 mg/L are determined to 0.1 mg/L resolution

Replacement reagents available

  • There is no need to buy a new kit when reagents are exhausted. The HI3875-100 reagent set can be ordered to replace the reagents supplied with the kit. This reagent set comes with 100 packets of HI93701-0 free chlorine reagent and 1 (500mL) bottle of deionized water.

Significance of Use

Disinfection is a process of killing disease-causing organisms (or pathogens). Chlorine (Cl2) is a very desirable disinfectant because, when mixed with pure water, it reacts to form hypochlorous acid (HOCl) and hydrochloric acid (HCl). HOCl (free active chlorine) is the most effective form of chlorine for disinfection of pools, spas, and drinking water.

Drinking water municipalities add elemental chlorine to the water supply as chlorine gas, liquid sodium hypochlorite, or dry calcium hypochlorite. In water these form free chlorine ions, which destroy disease-causing pathogens, reduce odor, eliminate bacteria and help to remove unwanted elements. The USEPA requires that residual disinfectant is present in finished drinking water to ensure there is disinfectant available throughout the distribution system, with chlorine acting as one of the disinfectants that provides said residual. However, the EPA has also set a maximum contaminant level of 4.0 mg/L for free chlorine due to potential health effects above this level.

Additional information

Weight 0.98 kg



SKU HI3875
Name Free Chlorine Medium Range Test Kit – HI3875
Free Chlorine Measurement Type Checker Disc
Free Chlorine Range 0.0 to 3.5 mg/L
Free Chlorine Resolution 0.1 mg/L
Free Chlorine Number of Tests 100
Chlorine Method DPD
Weight 984 g (34.7 oz.)
Dimensions 235 x 175 x 115 mm (9.2 x 6.9 x 4.5 in.)

Ordering Info

HI3831F test kit comes with HI93701-0 free chlorine reagent (100 packets), 500 mL deionized water, checker disc, glass vials with caps (2), and 3 mL plastic pipette.


Free Chlorine Medium Range Test Kit – HI3875