Buy this item and earn 18 points valued at $0.36.

Sold in bottles of 50 test strips (part# 481026) with a detection range of 0.0, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1.2, 1.5, 2.0, 4.0, 6.0 mg/l, SenSafe™ Free Chlorine Water check is affordable; with a retail price for either packing option of only $17.99. That's only $0.36 per test (based on a bottle of 50 test strips).

Chlorine is a common disinfectant used in automated watering systems. At lower concentrations, it is used to disinfect animal drinking water or to pretreat the feedwater to a reverse osmosis purification system. At higher concentrations, chlorine is used to sanitize rack manifolds, recoil hoses, and room distribution piping. A chlorine test kit must be used to measure the concentration of chlorine in water.

We are often asked:
"What does my chlorine test kit measure?"
"What is the difference between free and total chlorine?"
"Which form of chlorine is the best disinfectant?

Forms of Chlorine in Water
Chlorine test kits measure either free chlorine or total chlorine in water.

Free Chlorine - Free chlorine is defined as the concentration of residual chlorine in water present as dissolved gas (Cl2), hypochlorous acid (HOCl), and/or hypochlorite ion (OCl-). The three forms of free chlorine exist together in equilibrium.

Combined Chlorine - Combined chlorine is defined as the residual chlorine existing in water in chemical combination with ammonia or organic amines which can be found in natural or polluted waters. Ammonia is sometimes deliberately added to chlorinated public water supplies to provide inorganic chloramines.

Total Chlorine - Total chlorine is the sum of free and combined chlorine. When chlorinating most potable water supplies, total chlorine is essentially equal to free chlorine since the concentration of ammonia or organic nitrogen compounds (needed to form combined chlorine) will be very low. When chloramines are present in the municipal water supply, then total chlorine will be higher than free chlorine.

Introduction
This test strip method is designed as a screening test for free chlorine in a drinking water matrix. The analytes measured by this method are known as "free chlorine’ and include hypochlorous acid (HOCl), hypochlorite ion (OCl-), and un-disassociated chlorine (Cl2). Chloramines at levels typically found in drinking water do not have an impact on the method. The patented method (#5491094) typically requires less than one minute per test

To perform the method the operator dips one test strip in a 50 ml sample for 20 seconds. The strip is removed, and after a 20 second wait, is compared to a calibrated color chart.

Scope and Application
This procedure detects free available chlorine in drinking water.
This method is based on the reaction of 3,3', 5,5' tetramethylbenzidine with hypochlorous acid, hypochlorite ion, and un-disassociated chlorine (CAS# [77782-50-5]).
The method is acceptable for use in potable water.
This method is not for use with preserved samples. Samples should be analyzed immediately.

The detection limit is 0.10mg/L (or ppm) as determined in drinking water. The method applies to the range of regulatory importance of 0.20ppm to 2.0ppm free available chlorine.

Each laboratory that uses this method must demonstrate the ability to generate acceptable results using the procedure in Section 9.0. Each analyst must be able to accurately differentiate the color variation represented on the color chart supplied with the test strips.

Summary of Method
A test strip is configured with a pad attached to a plastic holder. The pad is attached across an aperture (window) cut into the strip at the end opposite the handle. The end with the aperture is placed in a 50 ml sample, with gentle motion, for 20 seconds. The test strip is removed. After a waiting period of 20 seconds, the color of the strip is compared to colors on a calibrated chart.

This is a colorimetric method. Color is generated by the reaction of 3,3', 5,5' tetramethylbenzidine (TMB) with the free available chlorine species. The amount of color on the strip is directly proportional to the amount of free available chlorine in the sample.