Most SPC treatments we monitored failed to meet the targetdose, but dose at the inlet was often lower than at the outlet, partic-ularly at the end of the treatment period. Rach et al. (1997) and Rachand Ramsay (2000) observed that HP doses were higher at the inletand decreased as the product moved through the system due todilution. This difference is likely to be due to incoming water flush-ing 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 dosewithin 15 min of application; dissociation and release of HP fromthe product is gradual.