Japanese oyster shells 20kg

Even if the tap water is quite hard, it certainly cannot be ruled out that problems with the KH and pH value of the pond water will not arise. KH is something of a buffer for the acidity (pH) of the water. Fish, plants and the biological filter "consume" the water hardness (KH). If, for example, little water is changed in the winter, the KH can drop quickly. The KH value also drops quickly in periods of heavy rainfall. This has major consequences for the fish, as the pH value can then suddenly drop sharply (so-called pH crash).

The KH value in the pond is often not measured regularly enough. Only in the event of problems, when it is already too late, are interventions made by adding agents such as KH+ powder. However, KH+ powder has several disadvantages:

A lot of the powder disappears very quickly through the bottom drain/filter system
Short-term boost effect, large fluctuations in water values
Always have to measure and add powder
Oyster shells guarantee complete stabilization of KH and pH over a long period of time. Oyster shells only slowly dissolve when the KH drops and buffer the pH in this way. Completely independent of the amount of rain, water changes or time of year: oyster shells automatically maintain the KH level and a stable pH. Only when the oyster shells have almost dissolved should you replenish them with new shells. An approximate figure is 5 kg of oyster shells per 10 m3 of water volume per year; the exact requirement is of course very dependent on the influences as described above.

Oyster shells are washed with chlorine and then dried: a guarantee that they are free of any harmful bacteria, mold or germs. The shells are also very suitable for use as biological filter material in a trickling or multi-chamber system.