I ended up using 1 tsp per 2 gallons. I am using it to get rid of ich i think it is working my fish seem to like it. i have a pictus catfish, a common pleco, a red belly pacu, a jaguar, a jack dempsey, firemouth, jewel cichlid, and a black skirt tetra. my tank is 55 gallons.
i know now i could have saved some money but it is my first time using salt and i just wanted to be safe. and i dont know what i would do with 40lbs of salt either ROFL