I believe any epsom salt brand would be fine as long as it has no additives.
Aquarium salt is Sodium Chloride.
Epsom salt is Magnesium Sulfate.
Epsom salt is a laxative. It will help constipated, bloated fish.
Aquarium salt is for treating external infections and will control fungal infections and protozoal infestations.
Here is a direct quote of OFL:
Originally Posted by Oldfishlady
Epsom salt is magnesium sulfate and helps to reduce swelling and works as a laxative among other things
Aquarium salt is sodium chloride and help healing wounds, external parasites, nitrite poisoning among other things
Both have a antibacterial/fungal properties
Both are great to use for short term treatments in salt tolerant fish when used in the correct dosage and duration for the right reason...