The SentiLiter app is a part of a network-enabled system including required SentiLiter hardware components which works to measure changes in fluid level, rates of fluid flow, and fluid color specifically in IV infusion bags, catheter bags, and drainage bags for medical patients. The system is designed to provide alerts to the appropriate caregivers remotely to reduce the need for them to check each bag manually, saving caregiver time and effort and improving overall patient care by having issues attended to more quickly. The alerts are intended to notify caregivers when bags will need service soon – typically when an IV bag is nearly empty, a catheter bag or drainage bag is nearly full – or there is a significant deviation or change in the flow rate of the fluid, which could indicate a problem with the fluid tubing or that a patient has begun to produce output into a catheter bag after surgery.