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Copper and silver used by ancient Greeks to purify water

Ionising silver and copper

Ancient Greeks found that water kept in silver containers mysteriously purified, and algae didn’t grow in copper water pots. In the late 19th Century, water was passed through various porous materials impregnated with silver, creating positive ions and purifying it.

Today, an ion-generating device can be installed in the circulation system. It is made up of an electrode assembly (a copper and silver electrode) and the electronic control unit that supplies current to the electrodes. Electrolysis then passes either silver or copper ions into the water where the silver disinfects and the copper prevents algae growth. The benefits are numerous:

  • The Ions in the water continue to disinfect even when the system is not running.
  • The Ions are not affected by heat or sun-like typical chlorine or salt chlorinators so there is no need to add chemicals such as stabilisers to protect the water.
  • TDS (total dissolved solids) are at extremely low levels providing crystal clear water.
  • A well-balanced pool using ionisation rather than high levels of chlorine can be back washed direct to your garden and is better for pool equipment and surrounds.
  • Ions in the water provide a softer feel, making you feel more refreshed and rejuvenated after swimming.

Purification and balance

Electrolysis of metals does purify but it does not chemically balance the water. See Water Balance Fact Sheet 5 to correctly balance the water.

Silver and copper residual levels can be measured, however, the registration authorities require maintaining chlorine or chlorine-free disinfectant residual as well.

The metal ions kill algae and bacteria but they do not oxidise organic waste. In days gone by, it was necessary to ‘shock treat’ or ‘super chlorinate’ the pool to oxidise any build-up of organic waste and maintain disinfecting action.

Technology advances have now seen a change with Hybrid systems such as the NKD-R Freshwater System, which combines both Ionisation along with Oxidation. The water passes over the metal rods and through an oxidisation process, similar to a saltwater chlorinator, but with much less chlorine produced. In fact, no more chlorine than what is in your household tap.

The system combines Silver and Copper to disinfect and prevent algae growth while Oxidation along with your pool filter removes organic waste such as oils from the skin, dust or other debris that comes from pool surrounds and swimmers.


There are now many alternatives on the market as opposed to standard chlorine or salt chlorinators. They can include the use of Ozone, UV Light, Bioguanide, Hydrogen Peroxide and of course Ionisation. We can only suggest you speak with your pool builder or an experienced consultant as to what is the best solution for your new or existing swimming pool and spa.

Here are some of the benefits of the NKD-R Hybrid Freshwater System.

  • Ideal for asthmatics, psoriasis or eczema sufferers
  • Typically running costs are 50% lower than traditional systems
  • Backwash direct to your garden to avoid water wastage
  • Longer lasting equipment and pool surrounds
  • No need to wash swimwear or shower after use as your water is no different to that from your household tap
  • No red eyes or irritated skin
  • Your pool will look amazing with crystal clear, freshwater

If you would like to discuss sanitisation for your pool or spa, please don’t hesitate to contact us.