A peritoneal dialysis system includes: a drain container a drain line placed in fluid communication with the drain container and configured to be placed in fluid communication with a patients peritoneal cavity a vacuum source configured to apply a pneumatic force to cause used dialysis fluid to flow through the drain line from the patients peritoneal cavity to the drain container a weight sensor configured to output a weight of used dialysis fluid delivered to the drain container from the patients peritoneal cavity and a controller configured to: (i) determine an actual flow rate of used dialysis fluid removed from the patients peritoneal cavity based on the output from the weight sensor (ii) compare the actual flow rate to a desired flow rate and (iii) adjust the pneumatic force applied by the vacuum source to attempt to match the actual flow rate to the optimal flow rate.
