Tonga Pearls are a completely new and thus a unique lime material, produced under quality controlled conditions, its composition and crystal structure corresponds to natural coral sand. Due to its texture and very white appearance, Tonga Pearls is ideal as a substrate in saltwater aquaria.Aqua Medic Tonga Pearls+ newly developed, white substrate+ produced under quality controlled conditions+ resource-saving not extracted from nature+ chemical structure corresponds to natural coral sand+ no fossil material+ suitable for use in all saltwater aquaria+ must only be rinsed a few times before useAlso for invertebrates such as anemones, cylinder roses, tube worms and wrasses Aqua Medic Tonga Pearls is optimal as the animals can dig with ease. Furthermore, this substrate is easily shifted by gobies. Tonga pearls correspond to the calcareous skeleton of corals in their crystal structure and this is the basis for a well-functioning aquarium. Tonga Pearls is not a fossil material. It is neither o