Hmmm I wouldn't risk it.
Dave is correct - "Top Fin" is Petsmart's store brand, most of their stuff is made by UPG (Marineland, Tetra for aquatics) but most of it is low-end stuff.
UPG also owns Aquarium Systems - Instant Ocean/Reef Crystals but it's hard to say what 'brand' of salt would be in that.
I wouldn't chance it.
Jenn