Green pond water

Filamentous algaeGreen pond water is caused by tiny floating algae, which grow explosively. Additional effects are low CH value, high pH value and stagnation in growth of oxygen producing plants. Green pond water frequently occurs in newly built ponds containing water rich in food.

What to do about a green pond

There are a number of measures to fight green water in your pond.

  • Apply a sufficient amount of bottom substrate. It is a good place for bacteria to adhere, thus securing activation of micro-organisms.
  • Apply more pond plants which do not have to rely on the water for their CO2 provision. So, apply floating plants, water lilies and marsh plants.
  • You should see to it that the total hardness (GH value) of the water is at least 12° GH (improve the water quality with GH.

Once the above mentioned measures will have been taken, the pond water will become clear in about 2 months. In order to expedite the result, in addition to the measures referred to you can add a “clear water” preparation and /or a filter equipment can be installed. Also an UV–C filter will do a good job here. The UV–lamp, however, should be replaced annually.

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