Is hard water treatment beneficial or damaging for koi carp and other ornamental fish?

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Hard water pool treatment can save you a whole bunch of problems when it comes to your prized koi carp or other ornamental fish, including those kept in aquariums.

But please read on before you rush out to buy a traditional water softener as these can be harmful to your fish and the ecosystem of your pond or aquarium. Instead consider using a hard water treatment system that inhibits scale yet leaves the beneficial minerals in the water.

In this blog we will highlight the importance of removing lime scale which will keep your fish healthy, save you money on costly equipment repairs and replacements, and time spent cleaning filters, air stones and pipes.


Experts in water saving technology and hard water treatment.

Let’s start by telling you who we are.

At Ecocamel, we are highly experienced in water saving technology and hard water pool treatment, our reputation has been hard earned from designing and supplying innovative, affordable and effective technologies and treatment systems from our London base for over 20 years.

(above) Ecocamel XL Magnetic Descaler
(right) Plantsurge Magnetic soft water device clipped to aquarium pump.

As a British company we have a strong presence in both the domestic and B2B water treatment industry - proudly selling over 40,000 home Ecocamel Descalers and as a leading supplier to the UK caravan industry, we have sold hundreds of thousands of water saving shower heads.

Ecocamel has built a solid reputation for expertise in the UK water saving and hard water treatment sector.


Why hard water can be a win-win for koi carp and heated aquarium fish, but it’s not so straightforward

The good news is that hard water provides beneficial minerals (calcium and magnesium) which supports a healthy metabolism for fish and for your pond environment.

According to an editorial in Pond Informer, run by a growing community of pond professionals,

In aquatic culture, all things seem to point to a single conclusion: harder water is better for koi, so long as the hardness comes from calcium and magnesium’

Why is this? A major concern with soft water is the potential lack of dissolved salts, such as calcium and magnesium, which as part of hard water are important for the regulation of electrolyte (salt) levels within the blood of fish through a process called Osmoregulation.

The minerals in hard water also helps biomass flourish, locks up toxins more readily and keeps a stable pH, and a GH and KH above DH 6.

However, there’s a catch. The not so straightforward part is that the minerals create hard limescale, which if left untreated, will damage pond equipment, cause unsightly markings on your pond liner, clog up air stones and fish may be more prone to skin disease and get dull looking skin.


Why are traditional water softeners not suited for koi ponds and heated aquariums?

Traditional water softeners use sodium or resin like chemicals to remove the minerals calcium and magnesium that cause the limescale. Whilst most are effective at removing the scale, they also remove the minerals which are beneficial to koi health and the chemicals are harmful to fish, plants, and aquarium life.

Magnetic water treatment offers simple solution to limescale control

In contrast to traditional water softeners, which uses chemicals or sodium salts, magnetic treatment is a very effective solution to lime scale control, magnets stop scale from crystallising by keeping the minerals in suspension so they can remain in the water to help create the ideal pond and aquarium environment, giving you healthier fish and more abundant aquatic plants.

Importantly, no toxic chemicals are added to the water, and you have a 100% natural solution to the problem.

Koi owner reveals a magnetic descaler keeps his fish free from disease.

When we asked Ecocamel founder and koi carp enthusiast, Guy Cinnamon, for his personal experience of using the magnetic descaler, here’s what he said.

‘Since fitting and using an Ecocamel XL there is noticeably less limescale staining along the water surface of the liner, and the pumps and aeration equipment require much less maintenance. Before fitting the XL, I read that positively charged water, which is magnetised, has a beneficial effect on Koi Carp. I have personally found that since treating the water it helps Koi make the transition easily from very cold to hot weather without disease.’


To find out more about how magnetic scale inhibiting technology works, we need to look in more stalagmites and stalactites detail at limescale. Limescale is simply calcium carbonate which causes crystals to form anywhere the water flows. These crystals are made of calcite and aragonite, (geologically seen as stalagmites and stalactites) and it’s these crystals when left unchecked or untreated which causes the scale seen in the hard water. Magnetic fields keep the calcium minerals in suspension so they cannot create damaging limescale.


Scientist reveals how magnetic fields keeps scale suspended, and minerals untouched for ideal pond care

Magnetic water treatment and its effects on scale reduction has been evaluated by scientists. Professor Coey from Dublin University is a world expert on magneto electrochemistry and magneto biology and has conducted extensive studies on magnetic water, showing that when hard water flows across static magnetic fields, it changes the way water behaves.

Professor Coye’s *experiments revealed magnetic fields changed the ratio of calcite in favour of aragonite, the two compounds which make up the calcium crystals in hard water. Calcite makes scale cling to surfaces whereas aragonite is less likely to form scale and keeps the hard minerals in suspension, moving along with the water.

*Scientific Reference: Philosophical Magazine Vol. 92, No. 31, 1 November 2012, 3857–386 Magnetic water treatment – how might it work J.M.D. Coey, School of Physics and CRANN, Trinity College, Dublin 2, Ireland

But this isn’t the whole answer.

Magnetic fields create a larger surface area to trap hard water molecules to stop them causing limescale

Because hard water is jam-packed with dissolved calcium and magnesium ions, the water molecules tend to bind together in huge clusters with little surface area left to bond with all those extra calcium and magnesium ions, so they have no choice but to drop out of solution and form the hard limescale deposits.

Having naturally altered the calcite to aragonite ratio, magnetic fields cause the water molecule clusters to breakdown into active molecules with a much larger surface area and better bonding capabilities with the hard mineral ions.

The new structure of the water molecules allows the molecules to pick up and carry away the hard water minerals greatly reducing their chances of sticking to pipe surfaces, while allowing existing scale to begin to break down. These scale deposits will never return, lowering maintenance & materials costs and creating the ideal pond or pool environment for year after year.

Scale inhibitor technology supports a cleaner healthier pond and aquarium environment

If you are interested in pond/aquarium water that keeps the minerals in solution but controls limescale, why not join the many owners who choose to use an Ecocamel magnetic water treatment product Ecocamel XL magnetic technology offers a clean chemical free solution that requires no power or maintenance, does not require cutting pipes (you just screw it on), and will inhibit scale for years without requiring any attention, cleaning, or replacement parts.

Ecocamel XL fitted to a 50mm water mains pipe into Koi Carp holding tank

Courtesy Guy Cinnamon

The best-selling Ecocamel XL embodies a new generation of effective, eco-friendly cost saving scale inhibitors which are ideal for ponds while our new Ecocamel Descaler is the perfect fit for your aquarium.


Magnetic hard water pool treatment systems which inhibit limescale but leave minerals intact in the flowing water provides the perfect solution for a healthy pool (pond) and aquarium environment. Traditional soft water systems which remove the calcium and magnesium should not be fitted for use with koi or ornamental fish.

Ecocamel is a leading UK company that designs and supplies magnetic water treatment products specifically designed for ponds and its scale inhibitor technology. The XL Descaler uses powerful neodymium magnets that require no power but stay charged for a lifetime and never need cleaning, servicing, or replacing. Pond owners can simply fit and forget it. Here is a link to some more information:

See our standard Ecocamel Descaler which ideal for aquariums:

Let us know your experience of limescale issues in your pond or aquarium and tell us what you think about the positives and negatives of hard water and any home solutions you recommend treating lime scale.

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