Application Instructions

Notes on chlorine, ozone and pH value determination

Chlorine reagent A1 for approx. 150 measurements, content 16 ml
Chlorine reagent A2 for approx. 150 measurements, content 12 ml
Chlorine reagent B for approx. 150 measurements, content 16 ml
pH reagent indicator solution for approx. 50 measurements, content 16 ml

Implementation of the determination of:

1. Chlorine (free)

  • first 3 drops A1 (buffer)
    then 2 drops A2 (DPD reagent solution)drop into the empty cell. Fill the cell up to the 10 ml mark with water, stir or swivel slightly and measure after approx. 1 minute.result = mg/l free Chlorine

2. Chlorine (total)

  • Add reagent solution B for total Chlorine measurement as follows:
    in water sample above 3 drops of solution B
    add, swivel slightly and read value after approx. 1 minuteresult = mg/l total Chlorine

3. Chlorine (combined)

  • result of the determination 2.
    result of  the determination 1.
    = mg/l combined Chlorine

4. pH value

  • pH indicator solution for pH range 6,5 – 8,4
    6 drops in 10 ml water
    swivel slightly and read off the pH value.

5. Ozone (in absence of chlorine)

  • The measurement is carried out with the GPT photometer in chlorine mode.
    First 3 drops of solution B into the empty cell, fill up to the 10 ml mark with test water
    then 3 drops of DPD solution A1
    then 2 drops of solution A2 add and swivel, read value after approx. 2 minutes
    Result:read value
    x factor 0,677
    = mg/l Ozone


The drop numbers given above apply to concentrations up to 3 mg/l. For concentrations up to 6 mg/l, the number of drops must be doubled. For higher concentrations, the sample water must be diluted in a suitable way. After use, the dropping bottles must be closed again immediately with the respective screw cap – the caps must not be mixed up!

blue cap on bottle A1

white cap on bottle A2

red cap on bottle B

black cap on bottle pH

Store the reagent set in a cool place if possible.


Thoroughly rinse the vial and cap after measurements using the cleaning brush to eliminate carry-over errors and deposits.