Absolutely natural wood · does not affect the quality and purity of the water · can be planted with real plants and mosses. Expert tip:. With natural woods, it can happen that whitish deposits form on the woods. These deposits are caused by bacteria that feed on carbon compounds in fresh roots. If these carbon compounds are depleted, bacterial growth is reduced and the white coating dissolves. The coating is completely harmless to the aquarium, animals and plants. Before use in already run-in aquariums, we recommend soaking the wood for a few days and changing the water regularly.