How much salt

[Nicolascrnelson]

How much salt do i put in per gallon of water in my freshwater tank??

 

[ercnan]

For what purpose ?

 

[Nicolascrnelson]

Softer water

 

[ercnan]

Softer water

Umm....
Wrong approach IMO. Try adding peat in the filter/s.
Other methods are out there, but peat is usually the cheapest and easiest.