Magnetic water treatment


Magnetic water treatment is a method of supposedly reducing the effects of hard water by passing it through a magnetic field as a non-chemical alternative to water softening. Magnetic water treatment is regarded as unproven and unscientific.

Effectiveness

Vendors of magnetic water treatment devices frequently use pictures and testimonials to support their claims, but omit quantitative detail and well-controlled studies. Advertisements and promotions generally omit system variables, such as corrosion or system mass balance analyticals, as well as measurements of post-treatment water such as concentration of hardness ions or the distribution, structure, and morphology of suspended particles.

Hypothesized mechanisms

Duration of exposure and field strength, gradient, rate of change, and orientation along or perpendicular to flow are variously cited as important to the results. Magnetic water treatment proponent Klaus Kronenberg proposed that the shapes of solute lime molecules are modified by strong magnetic fields, leading them to precipitate as spherical or round crystals rather than deposit as sheets or platelets of hard crystals. Simon Parsons of the School of Water Sciences at Cranfield University proposed that the magnetic field reduces the surface charge on small particles, increasing the tendency to coagulate as large particles that stay with the flow rather than depositing as scale. However, an internal study in 1996 at Lawrence Livermore National Laboratory found no difference in preferred crystal structure of scale deposited in magnetic water treatment systems.
Liu et al. and Coey and Cass published research in 2010 and 2000 reporting that magnetic treatment causes water containing minerals to favor formation of a more soluble form of calcium carbonate.

Pipe material

The effect of magnetic treatment depends on properties of the pipe. The magnititude of the effect depends on pipe conductivity and surface roughness.

Related devices

There are related non-chemical devices based on a variety of physical phenomena which have been marketed for over 50 years with similar claims of scale inhibition. Whilst some are effective, such as electrolytic devices, most do not work.
Other uses of magnetic devices: