Yes that will be fine it's a tonic salt if you have it, if not household salt, one tablespoon to every 5 gals, but add it gradually some today and add the rest tomorrow, or in 4 hours.
Can you increase aeration as well.
If you have the interpet salt follow there instructions of how much to add to the tank.
Can you increase aeration as well.
If you have the interpet salt follow there instructions of how much to add to the tank.