Measurement of total chlorine

Using tablet tests with the colorimeter permits detection of very low levels of environmentally significant inorganic ions, including ammonium, chlorine, nitrate, nitrite and phosphate.

Using these tests you can detect levels likely to be found in drinking water, often at concentrations less than 1 part per million (ppm). Contact us for details of how to obtain the tablets.


  • test drinking water for levels of chlorine, nitrate, nitrite, phosphate, ammonium
  • test chlorine levels in pool water
  • test the water in ponds and streams for polluting nutrients such as phosphate and nitrate
  • test soil water for nutrient levels.

Used correctly the test tablets do not pose a significant risk.

Avoid skin contact.

The tablets used in this test detect total chlorine., i.e. free chlorine + bound chlorine that has reacted with other compounds such as ammonia.

Crush one tablet in 10cm3 of the water sample.

After 10 minutes* pour 3-4cm3 into a cuvette and read absorbance using blue light.

* The time needed depends on the temperature. Below 20°C a longer time may be required.
totalchlorine graph