Filtration rate tells you whether water is moving through a filter safely — but running the filter is only half the job. Sooner or later every filter clogs, and how well you time and execute the backwash that cleans it determines whether you get a clean bed and a strong next run, or a poorly cleaned filter that fails again in hours. This guide covers the three calculations a Class C operator uses to run the backwash side of the cycle with confidence: backwash rate, backwash rise rate, and predicting filter run time from the way headloss is climbing.
The Filter Operating Cycle, in Numbers
A filter's life between cleanings — its "run" — starts clean, with headloss (the pressure drop through the bed) at its lowest point, and ends when either the effluent turbidity starts to rise (breakthrough) or the headloss climbs to a preset maximum (terminal headloss) that the control system or the