Filter monitoring system

A method of determining flux of fluid across a filtration membrane, the method comprising:

• receiving, from a sensor, an initial flow rate of fluid on a feed side before fluid flows past a filtration membrane;
• determining a change in concentration of a species between an initial concentration of the species in the fluid on the feed side and a final concentration of the species in the fluid on the feed side after the fluid has flowed past the filtration membrane;
• determining a final flow rate of fluid flowing on the feed side based on the change in concentration of the species and the initial flow rate of fluid;
• determining flux of the fluid that has passed through the filtration membrane based on a difference between the initial flow rate of fluid on the feed side and the final flow rate of fluid on the feed side, and a surface area of the membrane;
• determining that the flux of the fluid is outside a predetermined threshold;
• and
• adjusting one or more parameters to maintain the flux of fluid through the filtration membrane below a threshold value.