What makes treating water with magnets so alluring?
By Dr. Klaus Kronenberg
Article reprinted with permission from Aqua Magazine, August 1993
(Editor's note: this is the first of a two-part Tech Notes column on magnetic water sanitation.)
Everyone who sells swimming pools is deeply aware of the value of the liquid water, one of the most desirable commodities this earth provides. Nowhere else in our universe do we know of another place where liquid water exists. It is indeed the rarest matter of all. But this is not the only reason water is precious to us.
Water is the most necessary substance for life. In fact, living creatures -- like spas and pools are basically vessels for liquid water. Because we work in an industry that relies so heavily on sanitized water, it is imperative that we strive to understand how water reacts under various conditions. This is not always an easy task, as liquid water refuses to follow some of the most fundamental laws of nature. It is the one substance that turns into something lighter when it crystallizes-which is why ice floats. And even when liquid water cools down to near freezing it violates one of the basic rules that heat rises and expands things. As water cools down below 39 degrees Fahrenheit, it does not shrink, it expands! It expands so much that the coldest water moves to the top, above warmer water! That's why freezing starts on the top of the water. We should be happy it does that. Because of this solid layer of water on top, the rest of the water is insulated.
Another weird water fact is that it accepts more heat energy than its normal share-a great benefit to life. Indeed no other substance can transport as much heat energy. That's how liquid water normalizes the temperature extremes in out living zones-it absorbs heat when there is too much, and it releases heat if there is not enough.
HARD WATER FACTS
The list of the anomalies in the behavior of liquid water could be continued on and on. But we have to consider one more: Although water Chemically neutral, it is one of the best solvents known to man. Water has the capability to entrap other substances. In other words, it tends to cluster around every non-water particle, forming conglomerations or complexes, as they are called scientifically.
Water's Capacity to entrap substances results in its high mineral content. The amount of these dissolved minerals being carried by the water determines its hardness. One of the most common minerals in water is calcium carbonate, a substance that forms mountain ranges such as the Alps. When liquid water evaporated the dissolved minerals become over concentrated and must crystallize. This also happens when the temperature of the water increases,or when the solubility of the carbonates in the water decreases. The consequence is a sediment of those minerals on the walls of the container -- in our case spas and pools.
These sediments of minerals that grown on the container walls are actually limestone, which is hard and difficult to remove. Very hard water can produce these hard sediments with bad consequences. Unfortunately, this process is a slow one and cannot be recognized immediately. Nevertheless, the effects of hard water are quite noticeable if left to build up over time. Today the water lines that the Romans had used for hundreds of years show accumulations of hard lime scale many inches thick, as in the beautiful Pont du Gard in southern France, for instance.
But it only takes a few years for hard lime scale to take its toll on water pipes and equipment. Such sediment layers in heater hinder the transfer of heat.
For swimming pools the removal of existing hard lime scale is usually accomplished by an acid wash, which interrupts the operation of the system. Furthermore, the acid can attack pool walls and open up leaks.
Most water supplied by water districts in the United States is well cared for, analyzed chemically and rendered clean enough for drinking. Most of it contains a good amount of calcium content. This is important for proper taste and a healthy mineral balance. However, it tends to create deposits of scale over the years if no preventative measures are taken.
ROOT OF THE PROBLEM
Preventing scale can also be accomplished via water softeners, which work as ion exchangers. They take the calcium carbonate and replace it with sodium. The resulting water is not recommended for drinking because of the sodium content. And used in larger amounts, it also adds salt to the groundwater. Other chemical additives may rid the water of calcium carbonate, but only by risking contamination.
If one is serious about finding a cure for an undesired condition, it is essential that he or she find out what the source of the problem is. In the case of hard lime scale, the reason for it's formation is easy to understand with a few basic laws of crystallography.
The change from the dissolved calcium carbonate to lime scale is a phase change from liquid to crystalline. Any phase change needs a starting point. Most of the time a piece of a different material may serve as such a starting point. Such a piece can be extremely small, like a speck of dust, a super molecule or tiny solid particle. If such starting points are not available in the water, the crystallization can start only at the materials that make up the container walls. The crystallization grows in layers until it becomes lime scale.
Once we know what causes lime scale, the means of prevention seem obvious. We have to provide the necessary crystallization points for the minerals in the water so that the minerals do not wander to the container walls to find crystallization points.
How can we do that? By creating a disturbance in the water that produces crystallization centers for the minerals.
Actually, most water contains huge amounts of such centers. Almost all of these potential centers however are entrapped by the water-molecule complexes and cannot act as crystallization centers. Therefore, we have to break a few of these complexes so that their internal captive particles become free. Once free, they act as centers for mineral molecules and form microcrystals. That leaves less calcium carbonate to form hard scale on the walls.
Fortunately, an entire arsenal of complex-busting techniques is available. The disturbance can be mechanical whirling, sonic disturbance, electrical frequencies and magnetic disturbances. They all reduce the formation of hard lime scale to some extent. Lately, magnetic devices have become more and more popular for a number of reasons.
Permanent magnet materials have been developed in recent decades to be 100 times as strong and much more durable then the old-fashioned magnets made out of steel. In contrast to steel magnets, which weaken with age, modern ceramic magnets do not show any changes with age. They keep their forces so precisely stable that nuclear submarines base their subpolar, under-ice navigation on instruments depending on the accuracy of the permanent magnets. So, once they are, magnetized, permanent magnets never need recharging or an energy source, which makes their use most convenient and unfailing.
The effects of magnetic fields on running water have been observed long before these better magnets were developed. Patents on treatment of water with magnets appeared as early as the 1950s. Though these magnets were not very strong, their effects were described as making the water appear to behave as if it was softer, as if its mineral content was lowered. Noticeably less scale was produced after prolonged use.
This technology was used mainly in eastern countries, which were lacking a competent, reliable chemical industry. Hundreds of reports have popped up in Russia, China, Poland and Bulgaria detailing the successful use of magnets to treat water.
Lacking any chemical means of softening the water, these countries used magnets to treat water for irrigation and industrial uses, as well as for personal use, where improvements of taste and faster drying were reported. Many attempts to explain the reasons for the observed effects were made without much success. Also methods of measuring the effects remained unsatisfactory.
In western countries the use of magnetic water treatment methods developed much more slowly. Water softening by chemical means was in general use and the difficulties of explaining and measuring magnetic effect on flowing water kept it suspect for western minds. In addition the chemical industry tried to discourage its utilization for obvious reasons.
However the practical effects of magnetic water treatment were undeniable after prolonged use. A number of companies took advantage of the situation in western countries to market magnetic devices for water treatment, often equating magnets with magic or mysticism.
But there is no mystique in how magnets work to treat water problems. For example, the agriculturally oriented California State Polytechnic University in Pomona, Calif., Pioneered the reuse of irrigation water by using magnetic water treatment devices. The positive effects of magnets on water was confirmed in the 1980s through systematic research. With the scientifically sound knowledge of the processes involved , it was then possible to develop treatment devices with the newest permanent magnets. Also a quantitative method evolved for evaluating the effectiveness of the devices.
The new devices had a great effect on the water treatment. Not only was the formation of scale totally eliminated, the removal of scale deposits in old water pipes could be accomplished in relatively short times. This had taken weeks with the older devices.
How can magnets do that? How can they provide nucleation centers in the water? The shortage of nucleation centers in the water is known to result in form the capability of the water molecules to cluster around each foreign particle,rendering it unavailable as a nucleation center. The forces of the magnetic fields on those water molecule clusters is very weak. However the clusters vibrate in a number of ways. When they pass a number of magnetic poles at a certain velocity the periodic changes of the magnetic fields may coincide with one of the internal vibration frequencies of the water cluster. Resonance may occur and result in cracking open such a cluster. The formerly entrapped particle is set free, and the nearby mineral molecules rush form all sides to their nucleation center, where they form platelets.
The minerals that form the circular platelets do not have to crystallize on a container wall. In turn, the number of hard crystals is reduced accordingly. This percentage reduction is the magnetic treatments effectiveness rating.
Since a method of quantitatively determining the effectiveness of the magnetic devices was developed, manufactures have been able to maximize their efficiency for industrial and residential use. Today, there are basically two types of magnetic water treatment devices: one is built into the pools circulation system. While the other simply attaches to any pipe within the pools circulation system. In-line devices are usually more effective than the clamp-on variety. But naturally the clamp-on units are easier to install and are the most desirable for water systems that circulate, like a pool, thus giving the water repeated treatment over time.
Dr. Klaus J. Kronenberg is a physicist living in Claremont, Calif., specializing in the study of permanent magnets. Next month his column continues with further discussion of magnetic water treatment's specific application to the spa and pool industry.