Large-scale application of ferrous sand in aquaculture, ponds and aquaria

Green XL Pond Products and AquaMinerals have reached an agreement for the supply of ferrous sand (actually ‘iron-coated sand’) for application in aquaculture. The iron in the sand binds to the phosphorus in the water thus preventing growth of algae. It keeps the water nice and clear. But that’s not all. It also means that the phosphorus becomes more available for the water plants which therefore grow faster and bigger.

Dissolved iron is naturally present in many of the water sources used by drinking water companies in the Netherlands and Belgium. By adding oxygen to this oxygen-poor water, the iron precipitates. This precipitation takes place in sand beds specially built for the purpose. The sand beds are regularly flushed to remove the iron. However, over time, an iron film – or a coating – forms around the sand. This sand is then released (1) when the filter is rinsed through backwashing, (2) when the filter is scraped, and (3) when the filter completes its lifespan and is entirely replaced.

For years AquaMinerals has found destinations for these streams for its participants. But the development of a stable chain for them has always been particularly difficult. Ronny Theune, Commercial Manager, explains: ‘We refer to the material under a single name, ferrous sand, but the quality varies from one location to another. So, the grain grading, the amount of iron sludge present and, lastly, the thickness of the iron film are all different. And the buyers are of course looking for uniform quality.’

It’s possible to process ferrous sand into a product

The situation changed when AquaMinerals came into contact with the Koers company from Bovensmilde. Following extensive testing, they showed that they could carefully clean the sand while leaving the film intact. The material is then sieved into different fractions. Theune: ‘This allowed us to supply buyers with a continuous and controlled quality. The sand is now being used in surface water in different places in the Netherlands as a phosphorus-binding agent. This removes the nutrient source for blue-green algae, among others.’

Green XL Pond Products: natural products for ponds and water plants

Green XL Pond Products believes in the use of natural materials and products for sustainable solutions, and wants to actively contribute to the development of innovative chains. It has a natural pond-product line which, together with Moerings Waterplanten, it introduced to the European market this year.

About two years ago Green XL Pond Products and AquaMinerals got in contact with each other. Initially, the objective was to jointly study whether crushed calcite pellets could become part of the Green XL Pond Products portfolio. The discussions however turned pretty quickly to ferrous sand, a material that could fit nicely into the natural pond-product line.

Photo: Pond with water plants and crystal-clear water

Arie van der Weiden and Jeroen Flinsenberg of Green XL Pond Products rapidly became interested in the ferrous sand. ‘This product dovetails perfectly with our philosophy, since ferrous sand is after all a natural product. But we of course wanted to test it properly first.’ The tests produced striking results. The ferrous sand was also used in filters and in bio edges. During the tests the water became extraordinarily clear and the thread algae were kept under control. The ferrous sand was also used as a growth medium for plants. This produced exceptional plant and root growth. The clear water and healthy water plants make the pond visually more attractive for the consumer, and this is all achieved in a natural and biological manner.

Photo: exceptional plant and root growth

‘This, along with the rest of the natural line of Green XL Pond Products, provides us with a unique, natural and biological story,says Arie van der Weijden. It ensures optimal water quality and lavish plant growth. The result: a contented pond customer.

Product available at pond-specialists and garden centres

The biggest water plant nursery in the Netherlands, Moerings Waterplanten, distributes Green XL Pond Products and is very enthusiastic about the ferrous sand. So far, the results and experience in aquaculture have been excellent. The product can also of course be effectively used in ponds and aquaria, and it is greatly appreciated by consumers. In partnership with Moerings Waterplanten, it is now being marketed under the name BIO KORREL, and is available at pond-specialists and garden centres.

Photo: BIO KORREL package

According to Green XL[JA1]  Pond Products, the benefits of ferrous sand are:

–             The phosphorus values in the water drop very quickly, keeping algal growth under control.

–             The water becomes crystal clear.

–             The better availability of phosphorus makes for optimal plant growth.

For more information:

Arie van der Weiden, Jeroen Flinsenberg, Green XL Pond Products

Ronny Theune, AquaMinerals


 [JA1]Note the need to replace the I for an L here.

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