Patent ID: 7427355

Claim:
A water treatment unit for positioning in a container to treat water in the container which flows through the unit at low water pressure, the unit comprising: an elongated axis; an inlet for introducing water to be treated to the unit; a first chamber containing a first treatment medium which does not completely fill said first chamber when water is not flowing though the unit, said first treatment medium comprising a substantially loose particulate medium through which the water to be treated flows at low water pressure in a direction substantially parallel to said axis during treatment and which is lifted when the water flows through the unit at said low water pressure during treatment; a second chamber containing a second treatment medium though which the water to be treated flows in a direction substantially perpendicular to said axis at said low water pressure during treatment; a third chamber containing a third treatment medium through which the water to be treated flows during treatment, said third treatment medium including a magnetic field and at least one magnet and magnetizable particles; an outlet for discharging water which has been treated from the unit; and wherein the water flows from said inlet, through said first treatment medium, through said second treatment medium and from said outlet in that order and at said low water pressure during treatment.