*'''Media replacement''': Filter bed media can lose effectiveness over time due to clogging, chemical saturation, erosion, animal burrows, and compaction. Media may need to be replaced, regraded, or core aerated. | *'''Media replacement''': Filter bed media can lose effectiveness over time due to clogging, chemical saturation, erosion, animal burrows, and compaction. Media may need to be replaced, regraded, or core aerated. |