Silt, organic matter, fine particulates and other solid contaminants are best handled by multi-media filters — which remove these contaminants, and reduces the silt density index (SDI) of the feed water to acceptable levels, which protects downstream components from expensive damage.
Perform a silt density index (SDI) test on the feed water. An SDI of 5 or above will dramatically effect RO membrane performance — and indicates the need for multimedia filtration.
A high ΔP (pressure drop) across the filter shows that it is clogged. First, thoroughly backwash the filter to remove the particles clogging the media. Sometimes a clogged drain line flow control will keep the filter from backwashing at a high enough flow rate to backwash effectively.
Look for water running continuously to drain, system not backwashing properly, or a clogged drain line flow control.