Abstract: An assembly for the magnetic treatment of fluids such as liquids and gases. The treatment device is a hollow outer sleeve having magnets along the inside wall of the outer sleeve. An inner fluid conduit with a weak magnetic response can be provided in the outer sleeve. Different magnet arrangements produce different effects in the fluid being treated. An even-number of magnets arranged with alternating polarities around the outer sleeve are called a buster, producing an effect that tends to “bust” fluid molecules by introducing mechanical stresses and turbulence in the fluid. One or more magnets arranged with uniform polarity are called an aligner, producing an effect that tends to align fluid molecules with the magnetic field produced by the magnets. One or more busters and one or more aligners are often used together to form a magnetic treatment assembly. Magnets may be permanent magnets or electromagnets.