Phosphareduc Phosphate Fixer

Adsorber granulate and Phosphate Fixer on an iron (III) hydroxide base for the irreversible removal of phosphates from aquaria and pools. Can be used in fresh or salt water.

Method of use

To avoid clouding of the water, rinse before use in a bucket of water until the rinse water is almost clear. This will remove the remaining particles of dust from the production of the granulate.

Please place the little bag somewhere in the water circulation where it has as much water flowing around it as possible. For this purpose, the canister filter is of course ideal, as the quickest results can be achieved here due to the high through-flow.

Target values

The granulate has been designed for the rapid lowering of phosphate concentrations > 0.5 - 1.0 mg/l, which will not be lowered quickly or lastingly enough by change of water alone (particularly with higher concentrations of phosphate, the phosphate quickly re-dissolves out of the sediment after a water change with phosphate-poor water).

Please do remember that aquatic plants need a minimum quantity of phosphate to thrive, and do not allow the values to become too low (0.25 mg/l is an acceptable remainder). In tanks for fish only you need of course pay no attention to the above.

Mode of action

Existing phosphate dissolved in the water is in the first stage bound adsorptively to the highly porous iron (III) hydroxide surface. In a subsequent reaction it is converted to stable iron phosphate according to the following chemical equation:


Within a few days, the phosphate content in the aquarium or pond is effectively lowered, according to the extent of the original phosphate concentration and total quantity.


  • Very effective at low cost
  • High loading rates due to highly porous surface

Compared to iron or aluminium salt solutions

  • No change to the pH in the treated water
  • No entry of anions to increase conductance
  • Not a hazardous substance - no problems with storage and handling


A minimum of 15 g of phosphate / kg iron (III) hydroxide granulate according to the manufacturer's information
According to own measurements under the conditions of use, more than 20 g phosphate / kg of granulate are bound within 30 days.

As a positive side effect, silicate (silicic acid) is always bound in greater or lesser quantities alongside the phosphate.


After the depletion of the material you can either put the complete fleece bag into the non-recyclable waste, or open it with scissors and add the phosphate-loaded iron hydroxide granulate to your compost or compost recycling waste.

Package Contents

A suitable filter sock is supplied.

10 of 18 reviews

4.83 out of 5 stars






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18 June 2013 10:48

Zur Phosphatreduzierung im Bec...

Zur Phosphatreduzierung im Becken. Einfach den Beutel in den Filter legen. Einfache Handhabung.

12 March 2020 13:49

Sehr gute Qualität

Wirkung super

30 January 2018 08:58

Alles bestens ...

Alles bestens

30 January 2018 08:58

Alles bestens ...

Alles bestens

29 November 2017 11:11

Einfach zu handhaben ...

Einfach zu handhaben

9 August 2017 04:09

seit dem regelmäßigen Einsatz ...

seit dem regelmäßigen Einsatz im Aussenfilter (Topffilter) keine Probleme mit starken Algenwuchs mehr. Tipp: regelmäßig erneuern!

3 February 2015 08:01

Im Topffilter ...

Im Topffilter

20 December 2014 12:56

im Außenfilter unterberacht, p...

im Außenfilter unterberacht, praktisch und schnell untergebracht.

1 May 2014 11:26

der Beutel befindet sich im Au...

der Beutel befindet sich im Aussenfilter und leistet sehr gute Arbeit

21 March 2014 09:19

hat in meinem 450L Becken den ...

hat in meinem 450L Becken den Wert schnell reduziert.


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