Science Questions

Do magnets remove lime scale from water pipes?

Sun, 26th Apr 2009

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Question

Tony, Dereham, Norfolk asked:

I’ve been told a magnetic field can dissolve lime scale in water pipes. Is this true and how does it work since the pipes and I believe the lime scale aren’t ferrous and not affected by a magnet.

 

Answer

We put this to Dr Hugh Hunt, from Cambridge University's Engineering department:

I am Hugh Hunt from Cambridge University Engineering Department.  Well, there are lots of manufacturer’s websites that claim that if you put magnets on your water pipes then that prevents limescale build up on the element of your emission heater.  Electronmicrograph of limescaleWell it’s obviously in manufacturer’s interest to make these claims but lets suppose that in the last year a manufacturer has sold a thousand of these devices and they get one letter which says how fantastic it is, another ten letters that say that doesn’t work.  Well they can give ten refunds.  They have still made quite a lot of money and they can publish that one nice letter and I guess that not be what we are seeing on the websites but now that’s being a bit mean but I am a bit puzzled that there aren’t any quoted referred scientific publications out of the mainstream literature. 

Surely if there was something really scientific going on here it would be well and truly understood.  So I just wonder.  Now there are few possible candidate theories all to do with magneto hydrodynamics and water memory and things to do with nucleation and so on, you can read all about these.  Where does that leave us?  Well I think if you have found that one of these devices works for you, well it doesn’t do any harm so you may as well carry on using it.  But if you find that it doesn’t work then perhaps there’s no surprise in that. 

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I was told this too, by a plumber that was trying to sell me such a magnet for my very, very hard water.

I thought about it, laughed at him.

I later checked, and organizations like Which have failed to show any effect of these kinds of magnets.

I suppose a sufficiently strong magnet could in principle change the crystal structure if the field extended right through the boiler (since water is slightly magnetic), but the ones that they try to sell you that clip onto a pipe, before the boiler, it just can't work- the water would be disordered by Brownian motion within a few microns of leaving the field.
wolfekeeper, Wed, 22nd Apr 2009

I am amazed that these devices continue to be sold because I honestly cannot believe that they work. I can only think that perhaps some sort of changing magnetic field could induce a current in the pipe material perhaps electrolysing the water or the metal on the inside the pipe - but then again exactly what this would do I've no idea...

Chris chris, Fri, 24th Apr 2009

Wow, water memory got mentioned. I thought this was supposed to be a science show. Boo! Chris, Thu, 30th Apr 2009

I am an Electrical Engineer, BE, and a magnetic system design specialist. We have designed systems since 1991 when our shareholder was the CSIRO. The science of the transformation is not easily understood. The fact is that we have done trials in agriculture and mining. In mining applications we have engineers not believing the results but they have no choice but to buy the units because they clear the pipes. The deal was they pay only if it removes the scale. Within a few months they bought a second unit for a second line because it worked. Removed years of scale build up in a 6 inch underground coal mine pipeline at Mandalong in the Hunter NSW Australia. The fact is the magnetic field must be strong enough and the magnetic profile must be right. The laws of physics used are clear they are related to Lorentz theory. It is all about charged particles moving in magnetic fields. Just like an electric generator. Just like the old style TV or computer screen. Crystals just have to form differently. The difference between strings and balls coming together. The naivety of the so call intellectuals who are not willing to believe their own eyes. Reminds me of when the first positron was discovered. It appeared in an experiment with electrons which are negative. The positron positive charge was considered an error until some more open minded scientist realised that a positron may exist. Magnetic water conditioning works in most situations but it has some limitations controlled by the water chemistry. Certain element combinations are not as effected as others. That is true with all chemistry as not all chemicals react with every known element. There is a limited range of cases for their reactions. The truth about magnetic systems test results is that when scientist do tests on the treated water they are not doing correct tests. They do tests that test for certain reactions that would normally imply a certain substance present not the effect of the magnetic field. So the science being used to contradict the magnetic influences is based on limited scientific practices not real scientific research. They should be trying to work out why some observations do exist rather than saying that sometimes it doesn't work. I bet no one can pass a charged particle straight through any of our magnetic water conditioners without its trajectory being influenced by the magnetic fields. Scientists should realise that science isn't and end. It is a journey. Victor, Fri, 10th Jul 2009

Despite all my qualifications, I have no explanation of how a magnet around a pipe can change the properties of dissolved and suspended ions and compounds.
I live in a seriously hard water area, you pour a glass from the tap and it says "who you looking at? you looking at my bird? outside!"

One of my friends also an engineer said this sounds mad, but those magnet things work.

IT ALL DEPENDS.

Some people bolt one on and nothing changes. Noone knows how this works so not a surprise.

It is not a placebo, kettle descale has gone from 2 weeks to 3 or 4 months, there is still stuff there, but it appears to self precipitate as tiny foggy granules in the water rather than scaling the heating element.

There are snake oil specials like one company that shows a coil around a copper pipe, hmmm that`s going to do a lot at AC as you claim. NOT! I ignore these as also pointed out by "which?"

Whatever the current orthodoxy,  I  have found that despite all my internal objections based on my education this does work, in some locations so It needs proper investigation. What is the difference in assay between where it works and where it doesn`t? no-one has done these tests.

I bought one of these because it was stupidly cheap and I was drunk.

Sober I have to come to terms with the results, and I cannot explain them.





Edster, Sat, 25th Jul 2009

I think the best trial would be a blind trial whereby users were given real or "sham" units and not told which. They were then asked to report back on the effectiveness after say 6 months. Only when the results were declared and the code then broken to reveal a true effect will it be possible to say with any certainty that people are not merely reporting what they've like to see rather than the reality. chris, Sun, 26th Jul 2009

It is infuriating to have preconceptions dashed. Not double blind, but I had a negative expectation and I didn`t buy it thinking it would work,  it was a point of argument over a pint to wind a friend up over so he got defensive " oh well it was less than £5, what do you expect? Mine cost over £50 so of course it will work".


Much to my surprise It has done something as reported, I rinsed the kettle out recently, nothing on the plate element, no fizz from descaler.
I took the magnet thing off, and within a week spots of scale, that fizzed. Put back on and nothing. there is a slight haze as if a pinch of instant mashed potato or cornflour in solution sometimes which you don`t see with the magnet off.

It hasn`t done anything for the stored water in the loft tank that I can tell it still furs up anything it can.

Running the water and boiling immediately on plate type kettle (russell hobbs millenium) It isn`t scaling over the several months I`ve trialled it. It used to unless I filtered the water

I was adamant it wouldn`t work, copper is diamagnetic so it should be attenuating on a copper pipe, the geometry of the two magnets doesn`t encourage a radially piercing field, and was waiting to be able to say "didn`t work, sucker!".

I`ve worked on tape heads, hf and RF transformers and a variety things like TWT`s at the mod level from my phys/ electronics degree on. I cannot see how it can work, but the crudest put it on take it off test says it is doing something, but only on a fast flow near to the ruddy thing  and water subsequently boiled immediately.

It can`t do anything my head says in CAPITAL LETTERS   but the crude empirical evidence says it does. Fortunately there must be an eventual explanation, but I am at a loss and staying flexible.
this is real and observed not on drugs, and  a repeatable limited effect.

How many years have I heard anecdotally by otherwise sensible people this works? BUT ONLY in some places. A very good engineer now long retired, summed it up, "it looks like money for old rope, no-one has an idea exactly what is going on, It does work in some places, but £100 is a lot of money to risk if you don`t have it, and can`t take it back if it doesn`t work, I stick with chemical bags in the tank"






Edster, Thu, 13th Aug 2009

I installed an electronic one a couple of years ago or more. It's effect has been to produce softer scale which doesn't build up. You can scrape it off with a fingernail instead of a penknife and the kettle element doesn't look like a snowy scene any more. I don't need a double blind test; the evidence is pretty conclusive.

Btw, one of the Solar Heating companies (can't remember the name) expressly forbids the use of a magnetic  system cos it can clog the fine bore pipes with the very fine crystals that form. lyner, Sat, 15th Aug 2009

"I don't need a double blind test; the evidence is pretty conclusive."

That's exactly why you do need one. Bored chemist, Sun, 16th Aug 2009

The more esoteric effects I agree should be tested by identical houses, and installations( on a new estate?) by double blind with dummy units.

Empirically, due to my huge tea addiction, I can confirm that there is a cause and effect relationship between the permanent magnet and scale being deposited rather than hazing in solution in the kettle.

I was initially in denial but I have had to face the evidence.
I`ve stopped using my water filter to soften the scale which also made some tea show that metallic looking scum. The kettle is self descaler, once the scale reaches a certain thickness the flat element cracks the scale and a filter retains the bits. I`ve had this one 10 years, but 3 burned out due to scaling during the same period previously.

It has only made a difference to the bloomin` kettle, the valve in my tank has the filter clogged with scale yet again and the overflow is dripping, awaiting a cold day to go in the loft and drop the lot in vinegar.

Still It`s brilliant water for homebrewing strong ales! Hic! Edster, Tue, 18th Aug 2009


How many other engineering investigations involve double blind tests? Do they do double blind stuff at CERN?
You can do objective measurements and get objective answers without the need for double blind methods.  If I measure 12.3V on a meter, I don't ask someone to change the controls according to some random scheme and then do the measurement again. If there is an anomaly (a consistent variation from what was expected - not just a random error), I will look for an explanation. If I can't find an explanation, I will say I don't understand - not that the anomaly didn't occur.
This isn't medicine with placebo effects and self-healing systems (people)..
The only thorough investigation of which I am aware used a bench full of the old filter coffee makers. The build up of scale was clearly different with and without the magnetic inhibitor.  I don't see the problem that people seem to have with that.
There may be some chemistry involved which people don't understand but that doesn't mean that nothing happens. lyner, Sun, 23rd Aug 2009

the best way to test the effectiveness of magnets is to pour orange juice through a wine ring. As a liquid passed through a magnetic field it flips over some of the ions. + or - depending on which field you use S or N pole. Do you remember to make and acid or base one gives up and ion or takes an ion. So if you pass it one way it will give up ions making making the liquid more acidic if you pass it the other way it changes it to a bass. YOU can taste the difference. So in water softening you can only use a S pole magnet to do the work it will flip a hydrogen atom as the water passe through it changing calciumcarbonate to arognite. daniel, Sun, 8th Nov 2009

Well after just installing a Magnaclean filter. The answer is: Yes they work. But not on limescale.

I was advised to get a magnetic filter from a british gas engineer. I asked the same question. How can magnets remove limescale as its non-ferrous.

They don't. As they are sold to remove Iron Oxide that builds up as black iron oxide sludge that clogs up your boiler and rads. This was causing my boiler to go wrong all the time. I always thought it was limescale. After I saw the condenser they had to replace in the boiler I can see why. It was jam packed full of iron sludge.

So I've fitted one and 3 days later I checked the magnaclean filter and it does work. It had started collecting iron sludge before it had entered the boiler to do damage.

I will still have to clean the filter out from time to time mind you. But it looks like it's working.

I suspect the cheap limescale removers that advertise wrapping magnets around the pipe don't work. If they do have any effect it would be only on the iron. And would only build up on that section of pipe. Being there is no filter to collect the iron oxide. That in term would only block the pipe over time and you would have to cut the pipe out and replace it with a new section. But I doubt the magnets would be strong enough to attract the iron to the side of the pipe.

Link

http://www.adeysolutions.co.uk/subprofessional2.asp?id=246 VirtuaMcPolygon, Tue, 1st Dec 2009

I have some experience of this phenomena but not with the commercially made versions. About 20 years ago I was working in a job where I could get old loudspeakers for nothing and was also renovating a house in Bath where the water is hard. I saw that the magnetic water treatment devices were for sale so, being a skinflint, I put a toroidal iron speaker magnet around the plastic water pipe where it entered the house. The house had a gas boiler and a copper indirect hot water storage tank. My kettle did not get the usual hard coating of limescale but instead the water was misty when settled and had some loose particles of (presumably) lime. About two years after I fitted the hot water cylinder I was obliged to move it. When I drained it there was about six inches of pasty bright green sludge in the bottom of the tank but nothing sticking to the element or coils. I subsequently moved house (leaving the magnet where it was) to another house nearby and got hard limescale coating my kettle element. As I no longer had a source of speaker magnets but did have some spare neodymium magnets (half inch diameter about 1/8th inch thick with holes through the middle). I laid 11 of these stuck together along a horizontal 15mm copper pipe near the water entry to the house. My sink and kettle are about 15ft. further along that same pipe. The hard coating has ‘gone’, by which I mean I didn’t chip it off, and kettle-boiled water is cloudy with particles in it but they settle quickly. Hot water from my current cylinder is clear (to look at) and I have no idea what its like inside but it has worked OK for 18 years with nil maintenance. Obviously I have no explanation for how any of this might occur but if anyone wants to try it out they can do so for nearly nothing. Andrew, Sun, 27th Dec 2009

It never ceases to amaze me on how many (experts) there are out there ready and willing to negate something that they themselves have never tried. If you have never tried it, you are not an expert, you're a commentator. I know from experience that the magnetic affects on minerals in water is for real. My experience with magnets have been positive with boilers, commercial dishwashers, and ice machines. When the scale goes away without using acids and phosphate feeders, your magnet is working. Pretty simple. John Reid, Sat, 13th Mar 2010

I tried some magnets on my pipes for 3 months and they definitely resulted in less scale buildup. No scale rings in my toilets, faucets did not have scale buildup and sinks were easier to clean. Our water hardness is approximately 17 grains. I've yet to drain my hot water tank (electric), but I expect the heating elements will not have the scale buildup they normally do. I originally used three 4"x1"x1" ceramic magnets at the water main coming into my house and two the same size coming out of my hot water tank but now I'm experimenting with stronger rare earth magnets (2"x1"x1/4") to see if fewer stronger magnets can perform the same function. The magnets work. I don't know how, but they work. Jeff, Sat, 20th Mar 2010

Hi All, From our understanding a magnet Removes magnetite, rust and magnetic materials from heating systems to sub-micron level to stop sludge build up. http://www.fernox.com/equipment/filters/boiler+buddy If you have problems with calc/scale, the best thing is a quantomat : http://www.fernox.com/equipment/scale+reducers/scale+preventer+quantomat. If you have any more questions please get in touch with us www.busybees123.co.uk Mike, Director of Busy Bees Mike Williams, Mon, 19th Apr 2010

This idea is great works well I am provider of water pipe in uk,So these idea make sense simin, Wed, 1st Dec 2010

It's all about calcium carbonate that exists in three forms, aragonite, calcite and vaterite. If you can form aragonite crystals then you have taken some calcium carbonate out of solution and placed it into suspension. This effectively reduces the saturation ratio of the components necessary to form calcium carbonate that are left in solution. Calcium carbonate is inverse soluble meaning if you heat the water it'll try and dump calcium carbonate in the form of calcite. The lower the saturation ratio the less likely calcite will be dumped. The same applies to the other event that causes scale deposits, a pH increase. This occurs when pressure drops occur such as at shower heads and faucets. The drop in pressure causes carbon dioxide to be released from the water, carbon is acidic so when it's released from the water the pH of the water increases quite dramatically. In such situations scale can be deposited depending on the condition of the water. We've all seen scale build up on shower heads, that's why. A way to control and prevent scale is to use a water softener that removes calcium and other elements from the water by ion exchange or use a proven scale prevention unit, an example of which can be found below, this site has decades of case studies and a science paper from the Harwell atomic research laboratory to sink your teeth into: http://www.fluiddynamicsna.com Harry, Thu, 4th Aug 2011

For an explanation on the effect of magnets you could have a read at the paper I had to post in a blog because the kind of people who says that magnets do not work dogmatically also refused to accept it: http://chemistry-f-talens-alesson.blogspot.com/.

Essentially, ions in water have a bulk phase concentration and a surface excess. Surface excesses are often much higher, and they are the ones involved in reactions, including precipitation. Precipitation or other reactions will occur if the build up of those surface excesses reaches a critical value. That's what my paper is about, and also about how maths can deceive us into thinking that we know the mechanism of something when we only have a black box correlation.

The magnets simply beat back the build up of the surface excesses and prevent the precipitation. But it can work the other way round: some companies sell devices for descaling of water prior to its use that usg magnets. What they are doing is forcing the build up to form faster in a tank with the help of the magnets. The decalcified water is then used.

The bottom line is that magnets COULD be used to step up other reactions or to prevent them, for as long as the species involved or at least some of them are ionic. Nacho2012, Tue, 8th Nov 2011

Uh huh to all the above.

Where are the double blind trials that support these people trying to sell stuff?

There aren't any. If people want to sell me something, they're going to have to go through the publication process in a reputable journal; the plural of 'anecdote' isn't data. wolfekeeper, Tue, 8th Nov 2011



You seem not to have read or understood your own blog.
It doesn't mention magnets.

So, I could copy your post but change each instance of "magnets" to the acronym "SYFIYE" and it would be every bit as meaningful.

(SYFIYE =sticking your finger in your ear).

Bored chemist, Wed, 9th Nov 2011

water is ionic & freeze expansion is proof? Proper magnetization may work?
CZARCAR, Wed, 9th Nov 2011

About 1 part in ten million of water is ionic at normal temperatures and that falls a bit when it gets old. Ice is essentially non-ionic. Bored chemist, Thu, 10th Nov 2011

I see you are a very polite gentleman. If surface excesses of cations and anions circulate on a moving liquid in adjacent layers they can be regarded as two streams of opposite sign electric charges. If they do so under the influence of a magnetic field, they can be forced to either separate further, preventing them to reach out to each other (thus preventing precipitation) or they can be forced to run into each other, thus promoting precipitation away from the surface of the pipe in colloidal particles and not crystallising on the surface and adhering to it(the observation by some people on the forum that they noticed turbidity but not scale). Magnetic descaling of exiting deposits may be the consequence of depleting the liquid adjacent to the deposit from calcium and carbonate ions, and displacing the equilibirum. It would seem quite a trivial consequence of the solubility model I explain there. Nacho2012, Sat, 3rd Dec 2011


Water is not ionic. The expansion on freezing has been discussed at length.
magnetism doesn't work on water nor on the ions involved in making lime scale.
Bored chemist, Sat, 3rd Dec 2011

Interesting anecdote - read into it what you will.

Earlier this year I looked around some newbuild houses on an estate near me. A seen a few newbuilds over time, and these were some of the best build-quality I've seen.
When I checked out the plumbing under the sink, I discovered that they'd fitted a (permanent magnet) device around the plastic water pipe where it entered the property. This 'feature' was not advertised, nor pointed out by he sales rep. I just noticed it.
I would have thought that builders/developers would not spend money on anything that didn't benefit them in some way... do they know (or believe???) that this reduces call-outs on the boiler/heating system while the house is under the 10-year warrantee? techmind, Sat, 3rd Dec 2011


No  it isn't, no it isn't and no it doesn't respectively. Bored chemist, Sun, 4th Dec 2011

You would think that if these type of devices actually worked, they would give you a reasonable guarantee such as:

If the device fails to eliminate the calcium precipitation/scale problem, the company will:


Purchase & Install a competing Water Softener of the customer's choice at no additional charge, and
Replace any pipes that develop excessive restrictions due to calcium and mineral buildup, and
Replace any hot water heaters that have lost efficiency due to calcium buildup, and
Replace or repair any coffee pots/makers or teapots that have excessive calcium buildup with an equivalent device of equal or better quality, and
If an antique should become damaged by calcium buildup, it shall be professionally restored by the company, furthermore
In the event the company ceases business operations, the guarantee is underwritten by XYZ insurance company.


And, of course, having this as an open-ended guarantee, say in excess of a century, while the device is in use. CliffordK, Mon, 5th Dec 2011

Is there something odd about this thread?
I can't see my replies. Bored chemist, Mon, 5th Dec 2011



Odd,
I was sure I posted a reply yesterday.
And, it seemed to take a long time to post, but I thought it had gone up.
And... now it has vanished.


Anyway, my thoughts were that a company producing the calcium deposit magnets should be able to warranty the purchaser's pipes and appliances against damage due to calcium deposits, including replacing all the pipes in people's houses if there becomes a problem of excess mineral deposit in the pipes.
CliffordK, Mon, 5th Dec 2011

I certainly posted a reply to CARCZAR's post but it seems to have vanished
Water isn't ionic.
The expansion on freezing isn't related to that fact and the ions responsible for hard water scale are not magnetic. Bored chemist, Mon, 5th Dec 2011

water aint ionic & dont expand due to ionic nature? then why does it expand upon freezing?
CZARCAR, Mon, 5th Dec 2011

Hydrogen bonding. Bored chemist, Tue, 6th Dec 2011

thanx. i meant polar though glad to learn of H bonding. CZARCAR, Tue, 6th Dec 2011

I am really not sure if magnets work to remove lime scale from water pipes, but I do know that passing orange juice through a magnetic device I have for drinking liquids will allow me to drink orange juice and not have any heartburn from the acid in the juice even if it is cheap or inexpensive orange juice (it also works with wine and is supposed to work well with alcoholic beverages in general). I work for a company that manufactures an Electronic capacitor based water treatment system that absolutely does remove the scale from the pipes which is very obvious as you must open and clean any screen or filters to remove the old scale that has come off the water pipe walls. This was originally developed for the mining industry, and we have for chillers, cooling towers, evaporative coolers and heat exchangers as well as units for residential. It replaces traditional water softeners, does not add anything to the water nor does it remove anything from the water,  keeps minerals etc., in solution and does not allow to precipitate (stick to pipe walls). It still leaves the calcium on surfaces once water has evaporated, but you can simply wipe off instead of having to scrub or use chemicals to remove the scale. greenman, Sat, 17th Mar 2012

I was also big skeptic on this but the explanation that the magnetic field reduces the propensity to precipitate out, maybe somehow altering the way the crystals start to stack together, sounds quite plausible to me. This is lime scale I'm talking about, not Fe oxide Sprool, Mon, 26th Mar 2012

http://en.wikipedia.org/wiki/Magnetic_water_treatment

While it's not inconceivable that magnets could do something, basically, virtually all tests have failed to show any effect, and the ones that have, have not been independently verified. wolfekeeper, Mon, 26th Mar 2012



Well, it doesn't sound convincing to me.
Limescale isn't magnetic, nor are the ions from which it's made.
Bored chemist, Mon, 26th Mar 2012

Everything is slightly magnetic, it's not inconceivable, but it's not been proven to work. wolfekeeper, Mon, 26th Mar 2012



Well, it doesn't sound convincing to me.
Limescale isn't magnetic, nor are the ions from which it's made.



No, Not everything is magnetic. Some things are attracted to magnets, some- like water are repelled.
However it's important to remember that the effect of a magnetic field on most atoms or ions is tiny. Even the huge fields used in MRI machines only slightly  affect the protons  they image. The thermal motion knocks them back into random motion rather quickly.
The calcium ions typical of lime-scale are even more weakly affected by magnetic fields than the protons.
And, of course, these "magic" pipe-cleaners are not using huge superconducting magnets to generate a field like MRI scanners.
There si absolutely no way these things can work on lime-scale. Bored chemist, Mon, 26th Mar 2012

No, everything is magnetic, paramagnetic, diamagnetic, ferromagnetic etc. etc. etc.

So the question probably isn't really even whether it affects scaling, the question is whether it does it to a noticeable degree. It might even conceivably make it worse.

Most of the evidence seems to say it doesn't affect it measurably though.
wolfekeeper, Mon, 26th Mar 2012

I cant see how it could possibly work  If it did then surely it would only provide a limescale free band around the pipe where the magnet is...this theory was probably started by dippy hippies who think that crystals actually DO stuff that influence your life /health/happiness etc    IE complete crap !

pippystardust, Wed, 28th Mar 2012

Yes, I would think that as soon as it leaves the magnetic field that brownian motion and so forth would derange any alignment at all; it would decay ever-so rapidly.

I did read somewhere that somebody was getting a positive result, but that was later established to be due to them accidentally adding ions to the water, and the ions were changing the structure-they'd plumbed the gadget in wrongly and it was contaminating the water. wolfekeeper, Wed, 28th Mar 2012

Please nobody throw anything at me...but im a plumber/GasSafe heating engineer and I fit a device called a MagnaClean, it is fitted to the heating system and not the domestic (drinking/cleaning etc) water. Its basically a pot that is cut into the heating flow pipe with a magnet in its centre. This collects debris/sludge from your radiators and is quite effective. I never install magnets on the domestic side of a water system though. I have seen them before and id say if they do  work it may be down to the magnet lining up the positive and negative ions up so as they dont attract one another although how slow the water would have to run or strong the magnet would have to be for this to be effective im unsure. acecharly, Sat, 7th Apr 2012

Nothing wrong with using a magnet to collect ferrous metals fragments and associated sludge, that would damage a pump, or gum up your system, that makes sense... this is very different from using it to 'soften water'. daveshorts, Wed, 11th Apr 2012

I use magnetic plugs to remove ferrous debris from oil in pumps and compressors, as they then are not going to cause any further damage. Generally I get a light coating every few months of operation, pretty much normal, caused by wear of the cast iron bores. SeanB, Thu, 12th Apr 2012

I was sceptical about this; 45 years making a living in the electromagnetic and electronics world and I figured it was a load of codswallop. In the last three years I have been repairing a variety of laundry and kitchen equipment in a hard water area and without a doubt, where these things are fitted, be they electro-magetic or just magnets, they make a difference. As was said ealier, you still get limescale but it's softer and easy to remove. It must be something to do with the calcium molecules lining up with each other. The same argument is applied to the idea of magnets applied to fuel lines though I do not have any experience of that application.  Tunsarod, Fri, 20th Apr 2012

Data isn't the plural of anecdote.
Bored chemist, Sat, 21st Apr 2012

if you're 'bored' you might consider finding another field to consider for awhile. in that state not a lot of inspired awareness happening. but inspiration doesn't exist anyway, right? magneto, Sat, 28th Apr 2012

The pipe magnets DO work. I've been fitting them for many years. They don't prevent scale getting through (obviously :)) but the scale doesn't stick anywhere near as much to the pipework. The other thing is that if you fit the magnet to pipework which is already scaled-up, a lot of the scale comes off the pipe and blocks stuff downstream :) So you find e.g. shower heads getting bunged up with scale and having to be rinsed out, but this settles down after a few months. Peter, Tue, 22nd May 2012

This has been one of the most interesting discussions I have read for a while. (who's the geek, now?) I am changing my boiler and needed to know about this very subject about how lime could be affected by magnets or in any case how the lime could be jostled and not allowed to attach itself to the pipes and kettle. The Magnaclean commenter confirmed what a plumber giving me a quote for installation had told me. I had thought that the magnaclean's magnetic filter was also for the descaling. Now I am convinced that I will install both the magnatised water conditioner and the magnaclean, one for the household reality and the other for the boiler and radiators. I appreciated the pros and cons presented in the discussion. Fabulous how you all kept on topic and furnished a non chemical engineeer with enough information to make a decision. Thanx ladyfilosopher, Fri, 2nd Nov 2012

I am sales rep for a heating installation company and see a lot of boilers etc in homes recently i called to a 80 year old ex engineer who fitted a magnet to the water pipe he had probléms with limescale he said overa period of a year it removed all the limescale from his system include the water cistern in the wc etc . i am now going to do the same at home have blackswann, Sun, 4th Nov 2012

Looked up this site as I had just remarked to my husband that our gas kettle no longer has limescale in it after fitting a magnet to the incoming water supply pipe - it works! Jan, Sun, 18th Nov 2012

I was wondering whether the effect of these magnets on limescale has nothing to do with any effect on the copper pipes but rather something to do with the composition of the limescale itself. Looking it up on Wikipedia (not the world's most reliable source I know but also not as unreliable on science questions as some would think) I find that there are at least three limescale types that contain iron (Wustite, Hametite and Magnetite - FeO, Fe2O3 & Fe3O4) so maybe the 'works in some areas but not others' could be to do with the type of limescale minerals found in those areas, in the iron content of the water. Just a thought. Also I'm fairly sure that at some level magnetism can affect non-ferrous materials. Like inducing an electromagnetic field - like this: https://www.youtube.com/watch?v=E97CYWlALEs - so who's to say that it can't have an affect on the copper pipe or the calcium element of Limescale. Tim, Fri, 23rd Nov 2012

Fascinating debate. Surely this could be settled by means of a simple experiment? Run two lines of hard tap water, subject one to a magnetic field and leave the other alone. Test the outgoing water for conventional hardness, and filter and run crystallography tests for the forms of carbonate in suspension. At the same time the test could check for deposition over a longer timescale. Mass balance test on Ca to check that its all accounted for. Sort the question out once and for all! Anyone got a lab? PeterFW, Wed, 28th Nov 2012

I have personally used this method for stopping the build up of lime-scale for over 25 years, in France, America and now in England, the kits come with 2 double magnets which wrap around the pipe you fit them about 7 cms apart so the magnets are repelling, this changes the properties of the lime-scale particles and it then DOES NOT build up on elements, inside hot water pies etc. The prof who you sent it too for comment didnt even notice that the guy who prompted the discussion said  REMOVE how could it if it wasnt a filter???  jonnyleonard, Sat, 8th Dec 2012

Perhaps bored chemist would not be bored if he stopped theorising and carried out an experiment or two :) AndyJ, Mon, 10th Dec 2012

Perhaps bored chemist would not be bored if he stopped theorising and carried out an experiment or two :) AndyJ, Mon, 10th Dec 2012

Where the hell do these people think the minerals are going? Building up on the pipe until it's blocked? No, they aren't. Sean Smith, Sun, 23rd Mar 2014

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