Diagnosing low RO flow
Start by checking feed pressure, temperature, recovery, cartridge differential pressure and normalized permeate flow. Temperature changes alone can materially alter membrane flux.
If normalized flow is falling, inspect pretreatment performance, scaling indicators, differential pressure and fouling trends. Compare permeate conductivity and salt rejection at the same time.
Clean membranes only after identifying the likely foulant and confirming that the cleaning chemistry is compatible with the membrane manufacturer's limits.