Our guarantee
We GUARANTEE to give you your money back - even years from installation - if our LimeStops fail to stop limescale.  We are the ONLY manufacturer to do this.  We can do it because we know that our LimeStops work.  And in 19 years of manufacture, we’ve NEVER had to give anyone their money back!  That guarantee is your assurance that you are purchasing something that you KNOW will work.

In many areas of the UK, such as the Thames Valley, Kent and East Anglia in particular, rain water will pass through rocks that contain calcium and magnesium.  The water that filters through these rocks will partially dissolve these minerals.  Your water supplier will remove this underground water, clean it, and send it to homes across your region.  But the dissolved minerals remain.  When the water is heated (especially over 63 degrees C) the calcium deposits will fall out of the water and adhere to surfaces.  This is what's commonly called 'limescale'.  It’s highly damaging to water heating equipment and costs consumers millions of pounds per year.

However, you don’t have to resort to fancy ideas of protecting water systems from the damaging effects of limescale.  Water softeners are all well and good.  But they are expensive, and require constant salt replenishment and maintenance.  The problem with non-physical water conditioners, such as those that use electronic signals, is that they seem largely unproven, and manufacturers of these units are conspicuously reluctant to offer a money-back guarantee if they don’t work.  Polyphosphate inhibitors almost exclusively use a ‘dosing’ unit which has tiny holes for the water to flow in and out.  However, the holes block up with the powdery polyphosphate!

We have carried out research for many years on what works and what doesn’t.  Over thirty years of attending to hot water appliances that are encrusted with limescale has revealed that there really is only one choice - Siliphos, silicate-polyphosphate.  A Siliphos dispenser doses the water with silicate-polyphosphate.  So in 2003 we set out to find the perfect Siliphos dispenser for combi boilers - and, after constant improvement, the CombiBuddy (and LimeStop) were the result.  Since then, we’ve gone on to produce a range of limescale inhibitors over the years - backed by our infamous guarantee!

Siliphos is a widely-trusted food-grade material proven time and again to inhibit limescale formation.  Its ability to combat limescale deposits is really quite remarkable as it both lays down a protective layer on the walls of the supply piping AND inhibits calcium deposits.  Replacement of the units (every 2 years - at a discounted rate) can quite literally be a 5-minute job!  We’ll even remind you when replacement is due.  If you want to protect a whole-house installation more than three bedrooms, then opt for the LimeStop WH.


What is the LimeStop limescale inhibitor?
The LimeStops inhibit limescale from forming.  Some people call such devices ‘water conditioners’.

The majority of limescale inhibitors don’t work, do they?
No, they don’t.  Many such devices use magnets, electrolytic action, or electronic waves.  If they worked, then the manufacturers would offer you your money back on performance...but they don’t!  Here’s the ‘guarantee’ on a popular-selling ‘limescale inhibitor’...
We guarantee that your ********** will work for you. If you are not satisfied with the performance after 3 months continuous use, please contact us within 30 days of the end of this period
Really?  Four months?  It follows then that after just four months, when you find that this product (which costs more than £100) doesn’t actually work, then you won’t get your money back!  Here’s another...
If after six months of continuous use, you are dissatisfied with the performance of your water descaler, you may return it for a full refund
Again, after six months you’ll be unlucky when you discover it hasn’t worked!  What good is this?  If it really did work, then the manufacturer would surely be happy to give you your money back no matter when you made your claim?

So why is the LimeStop different?
The LimeStop range uses Siliphos - silicate-polyphosphate, so it’s classed as a ‘physical’ limescale inhibitor, in that it actually uses something to inhibit limescale – there are no smoke and mirrors!  Siliphos is remarkable stuff - able to positively halt limescale formation.

Is that why you guarantee it?
Yes, if you research ‘limescale inhibitors’ (on the internet) you’ll find that manufacturing companies of these devices will NOT give you your money back, years down the line, if they don’t work!  WE WOULD.  We can offer such an amazing guarantee because Siliphos really does work, even in very hard water.

Like where?
LimeStops have been installed in most parts of the UK, and have been sold in Ireland, France, Spain, Belgium, and Barbados.

What’s inside that inhibits limescale?
Siliphos - a food grade material called silicate-polyphosphate.

How does it inhibit limescale?
As water flows through the LimeStop it flows over the Siliphos particles - which give up a slight amount of their coating.  Siliphos inhibits limescale in two ways.  First of all the polyphosphate makes the calcium molecules stay in suspension, rather than stick.  Secondly the silicate lays a layer on the walls of pipes etc.  This too helps to inhibit limescale sticking.

Does it remove limescale that is already present?
Yes, but it takes time.

Does the Siliphos 'run out' of its effectiveness?
It degrades, that’s why a replacement is required.  We will send you a reminder.

So what will be the continual cost of the LimeStop?
The LimeStop 600 costs from as little as 9p a day!  The LimeStop 800 costs from just 10p a day, and the LimeStop 1000 just 12p a day.

Is replacement a straightforward swap?

Should I use a plumber to do that?
You could, but it really is quite easy.

Isn’t there a rival product to the LimeStop - one where you just replace the Siliphos?
Yes, but both the LimeStop 600 and 800 still work out cheaper (as does the LimeStop 1000)!  See below.

Is the water drinkable?
Yes, Siliphos is a non-hazardous, food-grade material.  It conforms to EN1208:2005 and WHO standards for drinking water supplies.  Unlike artificially-softened water, it's safe for babies too.

Is it classed as a water softener?
No, the hardness is still there, it's just suspended.  This is true of all limescale inhibitors; if a water conditioner doesn't actually remove the calcium, then it's not a water softener.

If the treated water is then stored, will it still be effective?
Yes, but the sooner the stored water is used, the better.

I don’t have a 15mm mains water connection
No problem, the LimeStop 600 is (primarily for combi boilers) 15mm.  The LimeStop 800 is available in either 15mm or 22mm for the same price, as is the LimeStop 1000.

What do I need to install it?
You may need some simple fittings, copper tube, a tube cutter, and basic tools.  You are also required to install a non-return valve - though your mains supply may already have one.

Your instructions say not to fit the LimeStop too close to a heat source, why?
Warm water back-feeding down the supply will degrade the Siliphos.  Its period of effectiveness would be less.

Is it easy to fit?
Yes, very.  Fitting should take no more than 30 minutes.

What if there is hardly any pipework to fit it on?
That’s no problem.  All you need to do is re-locate the LimeStop away from the piping.  You could route the piping both to and away from the LimeStop with flexible hoses, so you really need just 3” of piping.

Can I fit it in a cupboard?
Yes, but not if the ambient temperature is above 30 degrees C for the same reasons as above.  Also, fit it low down in the cupboard where the cold mains enters, as it would be the coolest part of the cupboard.

Will I still get limescale around my showerhead?
Most possibly, yes.  This is because although the Siliphos-effect will stop your shower scaling-up, 'still' water (water that doesn’t move) will be left on the showerhead and around taps etc.  The effect will be lost and deposits may well occur.  But these can simply be wiped away, as the deposits aren’t sticky.

What will the LimeStop protect?
The LimeStop range is made for ‘mains’ water appliances, such as mains-pressure thermal store hot water heaters, washing machines, dishwashers, shower mixer units, etc.

What about ‘Megaflow’ type units?
These use a store of hot water, but they are ‘heat banks’ and not thermal stores.  We can only state that the sooner the water is used after running through the LimeStop, the better.  The LimeStop 800 is perfect to protect thermal store hot water cylinders.

Will my water pressure be reduced?
All the LimeStops are through-flow units, and you would not see any noticeable drop in water pressure or flow after fitting.

Will the LimeStop withstand high water pressures?
Yes, they very robust units, able to withstand 6 bar pressure, with twin ‘O’ rings in the case of the LimeStop 800.  However, it is still strongly recommended that you install a pressure limiting valve prior to the BoilerBuddy or Deep Blue (set to 3 bar) if you suspect that your pressure is very high (over 4.5 bar).  You may already have a pressure limiting valve fitted to your water supply - many homes have.

Can you supply other versions?
Yes, we can.  Just ask.

What is limescale?
It's dissolved rock.  Rain water dissolves the calcium and magnesium out of the rock.  This water is then treated and sent to your home.  When the water is heated the dissolved particles re-solidify and stick to the walls of the heat exchanger.  It will do this at low temperatures, but it really begins at anything above 63 degrees C.

Is limescale harmful?
To your heating appliances, yes, very!  Even a tiny coating of it will reduce the efficiency of your appliance, meaning your energy bills will be higher.  It also causes premature failure of key components.  However, to your body, it is beneficial.  Remember, water softeners remove this beneficial calcium, the LimeStop doesn’t.

Why is the LimeStop better than other limescale inhibitors?
The LimeStop requires no electricity or maintenance - just replacement.  It doesn't use questionable electromagnetic waves.  It uses a time-proven material that we feel good enough to offer our performance guarantee of your money back.  And you don’t have to fiddle with large 'O' rings and wet Siliphos - you simply replace the cartridge housing!  You may be aware of a very similar unit to ours, but that device requires 6-monthly topping up, with annual cleaning and Siliphos replacement - see foot of this webpage.  You don’t have to do that with ours!

Do you guarantee that the LimeStop works?*
Yes, we do.  Our guarantee is that stated formally below.  We believe all limescale inhibitors should carry a performance guarantee.  Don't buy one that hasn't got a money-back guarantee.  Ours have, and we’re very proud of it.

Have you ever had to give anyone their money back due to re-scaling?
No, never...in 19 years.

Do you give a discount if I buy more than one?
We can only offer a discount if you buy three or more.  Please email us.

Can you install the LimeStop for me?
We can do this - the labour charge is usually around £60 plus any materials used - but only in the RG postcode area, sorry!  But any plumber can do it, and it’s not at all difficult for the average diy-er.  You may only need a hacksaw and a spanner!

How quickly can I get one?
We send our LimeStops by DPD.  It’s usually a next-day delivery, though this obviously cannot be guaranteed.

Can I come and buy a LimeStop at your door?
Yes, if you’re close to us (we’re in Reading, Berkshire) but call ahead first on 07702316157.

What about the CombiBuddy and the LimeStop TS?
The CombiBuddy and BoilerBuddy were both replaced by the LimeStop 600 (and contain much more Siliphos than either of those previous two for a cheaper price!).  The LimeStop TS is replaced by the LimeStop 800, and is much cheaper than the LimeStop TS.  The stainless steel LimeStop (containing 1 kilogram of Siliphos) is still available to order (please email us).

Why we are not on Amazon.
We don’t support Amazon and its practices.  We believe in supporting BRITISH retail outlets.

Why we are not on Ebay.
We don’t support Ebay and its poor customer support practices.

Why we will NOT offer PayPal.
PayPal is a very ineffective and poor payment facilitator.  It does NOT protect you in many circumstances, and its ‘Resolution Service’ even circumvents British consumer law!  It isn’t good for us, because PayPal’s charges would make our products more expensive, and it isn’t good for you because it takes too long to settle any disputes.  We advise that you are much safer using your credit or debit card, as that protects you under Section 75 of the Consumer Credit Act.

What the LimeStop is, and what it isn’t:
The LimeStop will stop limescale forming on the inside of pipes, etc.  It is not a water softener.  The ‘hardness molecules’ are still there, but the LimeStop WILL stop limescale by combining these molecules together to come out in the water - not sticking to heat exchangers or pipes.  That’s how it works.

The guarantee:
The guarantee against ‘scaling-up’ is dependent on the LimeStop being installed for 30 months and at least one replacement.  If the protected appliance/s* should ‘scale-up’ to the detriment of water flow (we would require proof to satisfy such an occurrence), then we would return the original purchase price of the LimeStop to the original purchaser.  Your statutory rights are not affected.
*Protected appliance/s: The unit purchased must be stated as suitable for its application.

Finally...a cost analysis of the LimeStop Deep Blue See against our nearest rival:

LimeStop 800 purchase cost (inc delivery) £85
CombiMate purchase cost (inc delivery) £134

LimeStop 800 replacement costs over 10 years £300
CombiMate replacement costs over 10 years £396

LimeStop 800 total cost after 10 years £385
CombiMate total cost after 10 years £530

Average costs taken from Google Shopping comparison July 3rd 2021.
4 x LimeStop replacements (every two years) at £75 each against 9 annual Combiphos replacements and top-ups.  No labour charges taken into account - which would further favour the LimeStop 800 over the CombiMate by a considerable margin, as the CombiMate would require labour attendance between 9 and 19 times, whereas the LimeStop 800 would only require labour attendance 4 times.  Please also note that replacement of the LimeStop 800 is straight-swap, whereas the CombiMate requires annual cleaning and replacement ‘O’ ring - with inherent water leak risk.