Quick take
Use coarse filtration first for sand and visible debris, then finer cartridges only as needed. Match micron rating to the actual particle load and protect downstream treatment.
Coarse sediment first
Spin-down or coarse filters are useful when sand, grit or larger debris is present because they can remove bulk load before disposable cartridges.
Fine cartridges
Cartridges in the 5–20 micron range are common polishing stages, but the correct rating depends on source water and flow requirements.
Absolute vs nominal ratings
Two filters labeled with the same micron size may not have the same capture efficiency. Certification and manufacturer definitions matter.
Protect downstream equipment
Sediment filtration often sits before carbon, softeners, UV and pumps to reduce fouling and maintain performance.