Marinero

What is the difference between the kind of salt you put in a freshwater tank and the kind used for a saltwater tank?

Gunnie

I believe aquarium salt is like epsom salt, and sea salt has trace elements in it which is necessary for the saltwater fish and the inverts in those tanks. I believe if you wanted to use the sea salt in your freshwater tank instead of the aquarium salt it would not be a problem.

Boxermom

Marine salt can be used in small amounts in a freshwater tank. Some believe it is better for livebearers than aquarium salt. However, aquarium salt cannot be substutited for marine salt in a saltwater aquarium.