The presence of chloramines can often be a concern when trying to test for free chlorine. It has been widely tested by Kuntze R&D, and other institutions, that Kuntze's free chlorine measurements do not respond and/or detect chloramines.
Note: Please consider the behavior, capabilities, and limitation of the reference measurement (DPD) in regards to this discussion. For more information, please contact your DPD reagent supplier and/or manufacturer to learn more.
Please refer to these articles for more information: