Rift lake salt will help a lot if you have low pH soft water Sean. It is a mix designed to add minerals to the water and raise the pH. It is unfortunate that it is called salt because that leads to confusion like we are seeing here.
Chemically a salt is any ionic compound that is composed of a metal and a non-metal ion. It is not the stuff that people mean when they tell you to add salt to a tank. My own tap water contains enough salts to register as a TDS of 325 ppm and to have a GH and KH both well over 10 degrees. The fact that those salts are mostly calcium carbonate and similar compounds does not mean that the water does not contain any salts.
The subject of this thread was a perceived need to add salt to an aquarium containing mollies. Worst of all was the idea that somehow sodium chloride, a compound that will only increase TDS but contains no pH buffers or hardness at all, was somehow a good thing for mollies. It is decidedly not a good idea. Even if you choose to use salts with a molly, the rift lake salts are a better match to their needs than aquarium salt but are not as good a match as sea salt.