SaltvsSalt

[midgetwaiter]

It's not even close to the same thing.

All but one of the salt mixes designed for aquariums are totally synthetic. They are designed to mix with water and provide a decent approximation of natural sea water in terms of mineral content. Different brands have different mineral levels.

The salt you are referring to is made by evaporating sea water and then processing the residue. This won't work in a reef tank for a long list of reasons but the most important one is that the dissolved minerals go through several changes during evaporation. Red Sea actually uses dried out sea salt as a base for their salt but they still add a bunch of stuff to it so it will make something like sea water when mixed.