Determining a volume of a container for dialysis treatment

A system comprising:

• a container containing bicarbonate and configured to receive RO water and deliver bicarbonate solution at a prescribed rate;
• a dialysis machine comprising:
• a pressure sensor configured to detect fluid pressure within the container;
• a dialysate fluid circuit configured to deliver dialysate at a prescribed dialysate flow rate;
• a fill valve configured to open and close to control a flow of the RO water into the container;
• and
• a data processing apparatus configured to receive signals from the pressure sensor, a signal indicating the prescribed dialysate flow rate, a signal indicating a prescribed bicarbonate setting, and a signal indicating a state of the fill valve as open or closed, the data processing apparatus configured to:
• based on the signals received from the pressure sensor and the signals indicating the state of the fill valve, determining fill parameters comprising:
• an amount of time elapsed between a completion of an initial fill of the container and an initiation of a first baseline fill of the container during a testing period;
• an average of amounts of time elapsed between each fill valve closing and reopening during baseline fill cycles of the container during the testing period;
• and
• a standard deviation of the amounts of time elapsed between each fill valve closing and reopening during the baseline fill cycles of the container during the testing period;
• determining a volume of the container based on at least two of the fill parameters;
• determining a depletion time in which the bicarbonate will be depleted from the container based on the volume of the container, the prescribed dialysate flow rate, and the prescribed bicarbonate setting;
• determining, based on the depletion time, an amount of time remaining before the bicarbonate will be depleted from the container;
• and
• causing the dialysis machine indicate the amount of time remaining before the bicarbonate will be depleted from the container to a user.