A method for operating a dialysis machine to conduct a dialysis treatment on a patient (e.g., a peritoneal dialysis machine) may include transferring dialysate from a first bag, and automatically determining the dialysate from the first bag has completely transferred. After determining the dialysate has completely transferred from the first bag, switching from the first bag to a second bag of dialysate. The method may further include transferring dialysate from the second bag in response to the detection of the completed transfer of the first bag, and automatically determining the dialysate from the second bag has completely transferred. The method may further include determining if the respective first or second bag has completely transferred by comparing a dialysate bag volume transferred to the patient to a detected volume of the respective first or second bag. Systems with dialysis machines for performing such a method are disclosed as well.