What grain size changes
Finer media forms a denser bed and retains smaller mechanical particles, but creates greater flow resistance. Coarser media allows freer flow and is often used as a transition or support layer.
Consistent grading matters as much as the nominal fraction. Excess dust and fines can increase initial turbidity and complicate backwashing.
What to check before ordering
Start with the filter manufacturer’s specified grain range, bed depth and flow rate. In multimedia systems, define the working and support layers separately.
- required fraction and acceptable fines content;
- material cleanliness and absence of clay or organic impurities;
- required volume, bed depth and layer arrangement;
- initial rinsing and routine backwash settings.
Loading and operation
After loading, rinse or backwash the new media until the water runs clear, following the equipment instructions. During operation, monitor pressure differential, filtrate quality and backwash duration.
Unstable performance can also result from incorrect bed depth, excessive filtration velocity or inadequate backwashing—not only from the media itself.