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It seems there are some electronic kits sold around nowadays by major retailers (e.g., Home Depot and Amazon) claimed to remove built-up scale from water pipes.

But, do they actually work? If so, then how?

Perhaps, inducing high-frequency eddy currents inside copper piping somehow lessens its ability to support limescale? Or, perhaps it gets broken down by some specific radiation (emitted by the kit) in the limescale's absorption spectrum?

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    $\begingroup$ I'm sure someone makes money, so in that regard I'm sure they work. $\endgroup$ – A.K. Apr 2 at 3:42
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    $\begingroup$ Yes , it is a scam . This has been discussed at National Association of Corrosion Engineers meetings for decades. The vendors have actually sold some to refineries; however they can never demonstrate good results in objective tests. The excuses the vendors find for the failures are a tribute to creative thinking. $\endgroup$ – blacksmith37 Apr 2 at 15:41
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    $\begingroup$ A.K. blacksmith37 +1 +1 I was afraid this was a scam, but thought it would be cool if there was indeed some kind of underlying concept or mechanism here beyond my (rather basic!) understanding of physics/chemistry^ What do you think of the theory presented below in Agriculturist's answer? $\endgroup$ – ManRow Apr 5 at 0:48
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    $\begingroup$ The "comments" remind me of the NACE meeting discussions. $\endgroup$ – blacksmith37 Apr 5 at 1:16
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These devices have been reported to work in some situations, but not in others.

The underlying theory involves altering the growth of calcium carbonate scale with an ordinary magnetic field. The magnetic field changes which form of calcium carbonate crystal (calcite, aragonite, and vaterite) is favored. Certain forms of crystal make tough scale while others can pass through a water system without scaling.

The growth and precipitation of carbonate crystals are affected by many other things such as calcium concentration, carbon dioxide concentration, temperature, pH, and the presence of other metallic ions. Exposure time to the magnetic field, magnetic field strength, and magnet orientation also have an effect.

The different forms of carbonate crystals can be tested to have specific properties under controlled laboratory conditions. Under uncontrolled conditions, the scientific literature is full of mixed results and mixed explanations. Because so many things affect the formation of scale, it is impossible to say if a magnet or device generating a magnetic field will work to thwart scaling in any specific situation. It may work wonderfully in some situations but not at all in others.

The best way to tell if such a device is worthwhile would be to see if several people using your same water supply report it as having worked lately. If water management practices change (e. g. factors affecting the formation of scale are controlled) then such a device may cease to work. If no one using your same supply can attest to its operation then this would be a risky purchase.

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  • $\begingroup$ Interesting, so what kind of magnetic field does the underlying theory then recommend? One that oscillates back and forth, or a constant one? If the latter, does it matter how it's oriented relative to the water flow? (i.e., parallel, antiparallel, or orthogonal) $\endgroup$ – ManRow Apr 4 at 23:39
  • $\begingroup$ sciencedirect.com/science/article/abs/pii/S0304885301004322 - this paper tested the commercial units against a magnet and found the magnet more effective. I do not think there was anything special about the magnetic field. $\endgroup$ – Agriculturist Apr 4 at 23:59
  • $\begingroup$ researchgate.net/profile/Vladimir_Zlotopolski/publication/… - This paper talks about its use in irrigation. It mentions contradicting claims surround what type of magnetic field is best. $\endgroup$ – Agriculturist Apr 5 at 0:02
  • $\begingroup$ I don't have access to Elsevier ($$$) for the first publication, but it looks like the researcher who published the second was actually working on behalf on the company behind the magnetic water treatment technology promoted in his paper at the time (so, there may have been a conflict of interest). $\endgroup$ – ManRow Apr 5 at 0:20
  • $\begingroup$ Also, that technology uses permanent magnets, while the kits in my original question require electrical power. In either case, it seems only an orthogonally oriented magnetic field (relative to the water flow) could possibly affect the ions' trajectories (via Lorentz force), but the kits in my original question can only produce a parallel (or antiparallel) one given the placement of their solenoids. $\endgroup$ – ManRow Apr 5 at 0:21

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