Most SPC treatments we monitored failed to meet the target dose, but dose at the inlet was often lower than at the outlet, particularly at the end of the treatment period. observed that HP doses were higher at the inlet and decreased as the product moved through the system due to dilution. This difference is likely to be due to incoming water flushing the solid SPC through the system in our study, diluting it moreat the inlet and concentrating it at the outlet over the treatmentperiod. Granular SPC treatments often failed to reach the target do sewithin 15 min of application; dissociation and release of HP fromthe product is gradual.