FIPROPLUS 905

It may be sufficient to measure the pH value which will be carried out with a special device or with an indicator paper; the values to be maintained depend on the way of working and must vary between 9 and 10.5.
A more exact control of the bath can be done by chemical titration according to the following method:
using a calibrated pipette, exactly 10 ml of bath are taken, diluted with 20-30 ml of demineralized water and added to 4-5 drops of green indicator solution of bromcresol. The liquid, which will take on a blue color, will be titrated with a 0.1 N hydrochloric acid solution until it changes from blue to yellow.
The n ° of ml of Acid used for the color change will correspond to the bath score, whose concentration can be traced back by consulting the following:

CONCENTRATION [g/l]            POINT [ml hydrocloric acid 0.1 N]

               5                                                                                    1.75

               10                                                                                  3.50

               15                                                                                  5.25

To obtain the concentration of the passivating agent, the n ° of ml of acid must be multiplied by the factor "2.86".
For the reconcentration of the bath, approximately 2.86 gr / lt must be added for each point found less than the set value. The alkalinity values can be varied by the salinity of the water.