BDH Lovibond Nessleriser/Tintometer. To determine the chlorine content of potable waters and swimming baths.
Method of Applying the Test from Instruction Leaflet. “Fill one of the Nessleriser glasses to the 50 ml mark with the sample of water under examination and place in the left-hand compartment of the Nessleriser. Fill the other Nessleriser glass to the 50 ml mark, add 0.5 ml of the ortho-tolodine reagent, mix, allow to stand for five minutes, and then place in the right-hand compartment of the Nessleriser. Stand the instrument before a uniform source of light – a north window is the best -and compare the colour produced in the test solution with the colours in the standard disc, rotating the disc until a colour is obtained. The markings on the disc represent the concentrations in parts per million of free chlorine when 50 ml of water is taken for the test.”