Abstract: Methods and apparatus for fluid conditioning to reduce scaling, inactivate microbes, reduce surface tension, maintain fluid composition, and improve pumping are provided for use in treating crude petroleum, industrial water, agricultural water, municipal water supplies, or any fluid flow system and comprise electromagnets of variable control that can be powered or in which a current can be induced by a permanent magnet. Magnetic field direction and intensity can be selected depending on the nature of the fluid and in some embodiments, the field can be varied during operation, including pulsing and variably selecting one or more field directions and intensities, or combinations thereof, during operation. A non-magnetic fluid transfer conduit section has at least one conductor assembly mounted about the section. In one embodiment, the conductor assembly comprises a concentric, tilted double helix coil or multipole coil.