01 Tap water

The composition of the ingredients in tap water is so complex and varied that no general statement can be made as to whether tap water is suitable for marine aquariums or not.

Ingredients in tap water such as water hardness (calcium and magnesium) are usually desired. Other substances, such as nitrate, silicate, residues of pesticides and medications, microplastics have no place in the water for a marine aquarium, or their concentration may only be in a very narrow concentration range. Also, an ionic shift can occur if tap water is used as refill water for the evaporated water. Especially sensitive SPS corals suffer very quickly as a result.

Using natural seawater is one possibility. Against it speak the transport costs, the inconsistent quality and the potential danger of parasite introduction.

We definitely recommend water treatment for use in marine aquariums. With treated water, the evaporated water can be re-filled without side effects, fresh seawater can be produced with a sea salt mixture and used for chemical analysis.