Palintest AP162 Chlorine HR Reagent Tablets 250 per box. The Palintest Chlorine HR test is based on an iodine release method. Chlorine reacts with potassium iodide in acid solution to release iodine which is brown in colour. The reagents for the test are provided in the form of two tablets for maximum convenience and simplicity of use. The intensity of the colour produced is proportional to the chlorine concentration and is measured using a Palintest Photometer.