First, Safe is a conditioner and should never be used to "treat" nitrite, except at a water change if nitrite occurs in the source water, or is present in the tank but that should not occur normally.
Overdosing conditioners is risky and the amount required to condition the fresh water is all that should be used; I am assuming fish are present. Substances added to the tank water will get inside fish if the ions are able to permeate the cell walls (this depends upon the size). The fish "drink" water by osmosis through every cell, and the water along with substances dissolved in it enter the fish's bloodstream and internal organs. The less the better.
If no fish are present, I guess it really doesn't matter, but I can't speak for invertebrates, plants or bacteria. Adding any chemical can have follow-up reactions chemically.