[Stefanie Rick]

I first put it in a bowl and scald it with boiling water, let it soak for a very short time – just until all granules are sunken. Then I pour it through a sieve to remove the hot water. After that I spread the granules on the bottom of the aquarium, in a very thin layer of about the grain size, just enough to merely cover the ground.
I think an amount of two cups is enough for a 20 l tank. Just try with a small amount – you can easily prepare a bit more if needed.