What does Minimum Deficit mean?

Minimum Deficit is the minimum amount of Deficit ET (displayed in inches) that needs to accumulate before the SmartLine controller will run an ET–based schedule. Deficit ET is the amount of water that needs to be replaced to plants due to water loss through evapotranspiration – evaporation from soil and transpiration from plants. Your SmartLine controller will calculate the water deficit each day at 11:50 pm based on data communicated to it by the SLW series weather station. Deficit ET will continue to accumulate until the Minimum Deficit is reached before applying the next scheduled watering cycle and will return to a zero reading when watering is finished. The setting is global for all zones in SMART Mode. The range for the global setting is 0.00 to 0.50 inches. The factory default is 0.15 inches.