Principle

The Residual Chlorine test is a colorimetric test, but is a little different from the other colorimetric tests here. We use a colour card rather than standard solutions. This test has a range of 0 to 3 mg/l.

Calibration

You do not need to make calibration standards for this test, just use distilled water for calibration.

  • Take 5ml distilled water in a 15 ml measuring tube.
  • Add 3 drops of free chlorine reagent in it and mix well.
  • Pour 5 ml of the solution into the cuvette.
  • Place the cuvette into the holder in the box.
  • On the next page click on Calibrate.
  • Align the colour card to the image displayed, the instructions on the screen would help, and press Start.
  • Click on Start Timer and wait the required amount of time for the reaction to take place.
  • The camera immediately opens up once the specific time is up.
  • Point your phone to get a uniform colour of colour solution and keep the phone on a light box to capture images of solution and calibrate.
  • In case of an error message while calibrating, re-calibrate.
  • On successful scanning, you will be shown the calibrated point and the colour shift.
  • Press Accept.
  • Your phone is now calibrated. You can now begin testing samples.

Note: Calibration needs to be done only once for every parameter. The Calibrate option changes to Re-calibrate when calibration is complete. There is no need for recalibration before testing every sample.

Test

  • Measure out 5 ml of your sample in a 15 ml measuring tube.
  • Add 3 drops of Free chlorine reagent.
  • Shake well to ensure proper mixing of reagents.
  • Pour 5 ml of the solution into the testing chamber.
  • Place the testing chamber into the holder in the box.
  • Put a Residual Chlorine colour card on the test chamber.
  • Click on Start Test.
  • Read the instructions on the screen and press Start.
  • The camera immediately opens up once the specific time is up.
  • Point your phone to align the green coloured grid on the screen with your colour card setup.
  • Your result will be displayed on the screen.