If my aro got fin problem. What medication to use?

[Goodman123]

Bros out there could you advise, what medication to use for fin problem? Example fin rot or damaged fin and etc?

Is it melafix or pimafix? Any difference btw this two? When should we use melafix and what situation then we use pimafix?

As for the salt content, how much to put in the water? For sometimes i hear people say 1% or 2% would do, but how do we gauge it? How to indeed measure that percentage? And if got fin problem , what is the amount of salt to put in the water? Please advise. Thanks