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Behind the so-called science of "no-salt" water softeners

"No-salt" water softners and other devices that use magnetic, electromagnetic, electrostatic, catalytic or mechanical means to treat water are commonly known as NCD's or Non-Chemical Devices. In this article, NCD technologies as a whole are discussed.

Excerpted from "Non Chemical Devices: Thirty Years of Myth Busting"¹
Review of the NCD supplier literature shows many common explanations for NCD operation, one theory often covering several types. However, we do note a certain amount of disagreement between some suppliers having the same basic type of unit. In order to address the many varied theories of operation, the clearest explanations found in the supplier literature are summarized in the following and examined against known scientific principals.

1. Device operation causes calcium carbonate to precipitate as aragonite, not calcite, generally as a bulk precipitation; and also causes any existing calcite in the system to recrystallize to aragonite.

To date, all controlled studies of devices claiming this ability have shown that the calcium carbonate continues to crystallize as calcite, not aragonite. In cases where the water pH has not increased by cycling, calcite does not bulk precipitate, forming instead a typical scale.

Bulk precipitation has been noted in many NCD treated high cycle systems, but is a function of pH, not operation of the NCD. Not addressing effects within the device itself, it is difficult to picture any downstream mechanism which could cause calcite to change to aragonite as calcite is the stable crystal phase of calcium carbonate. In fact, aragonite is the low temperature stable phase of calcium carbonate with a reported transition temperature of 128 C to calcite. Some reversion is reported in the literature, at a temperature of -60 C.

We would note that this ability is claimed, or inferred, by many of the NCD suppliers for their devices with claims such as "scale forming minerals change their ionic construction" or "dissolved solids precipitate as a loose powdery dust". While it all sounds scientific, aragonite will form in place of calcite only under well defined temperature and pressure conditions. Note should be made that the primary factor in dictating the crystal structure adopted is geometry of the ions, i.e. their size. Thus at low temperatures and high pressures, aragonite forms a denser structure than calcite and is thus the preferred phase. Exposure to electrical and magnetic fields have never been shown to effect the size of ions in solution. In addition, aragonite forms scales that are as hard and tough as calcite, so there would appear to be no good reason for preference of one cyrstal structure over the other.

2. Particles, or molecules, are charged, or their static charge is altered, by operation of the NCD in such a way that they repel each other, preventing formation of scale.

Cooling water is quite conductive and as a result any charge placed on particles, or molecules, within the liquid as a result of NCD operation would immediately short to ground.

We also note that calcium and carbonate exist in water solution as dissolved ions, thus they are not in a particle form. Exposure of these ions to the low level magnetic, electrical, or mechanical forces produced by the NCD reviewed will not alter their ionic state.

3. NCD operation alters the behavior of molecules, or particles, in the water by aligning their polarities to neutralize the adhesion required to form scale.

Not considering any effects within the device, any such polarity alignment would be immediately destroyed in the operating water system by simple Brownian motion.

4. Mechanically alters the Langelier Saturation Index by stripping out carbon dioxide and oxygen, forces calcium carbonate to form a non sticking solid. Kinetically breaks scale mineral chemical bonds.

Removal of free carbon dioxide and oxygen from a water have minimal effects on the LSI and no effect on the crystal form that calcium carbonate will take upon precipitation.

Due to the high energy levels needed, it is extremely unlikely that scale mineral bonds can be affected by mechanical devices. We also note that as calcium and carbonate are typically present as ions in cooling water, that there would be no crystal "bonds" to be broken by passage of the water through the NCD.

5. High shear produced by operation of mechanical NCD is reported to "crush and kill" micro organisms.

Interesting comment that may have some truth to it, but as the major problem in cooling water systems is sessile micro organisms, not planktonic ones, it is irrelevant to obtaining good microbiological control in cooling water systems.

 

© 2004 ProChemTech International, Inc. All rights reserved.
¹ Timothy Keister, FAIC, CWT. Original article can be found at http://www.prochemtech.com/Literature/Technical/ncd.html

 

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Consumer Alert: Eco-Friendly Water Softeners Suspect
What are Non Chemical Devices?
The Professional Opinion on "No-Salt" Water Softeners
Why Sketchy "No-Salt" Water Softeners Still Sell
5 Ways "No-Salt" Water Softeners Fall Short

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