For removing hardness deposits, a sample of scale should, if possible be removed from the plant and placed in a solution of the solvent at the temperature at which the clean will be carried out.
The solution concentration required is in the range of 50 – 100 kg/m3 of water depending on the quantity and characteristics of the scale being removed. The contact time also depends on a number of factors including the quantity and characteristics of the scale, the strength of the cleaning solution and the ability to recirculate this solution. However the recommendedcontact time is up to 6 hours.