Salt gravity of 1.014?

[Cleggat]

Okay guys, so I have been looking all over the net for this and I am getting mixed answers but the best place for answers is here, I want a salt gravity between 1.014 - 1.016 for a ten gallon tank. It's for a water change so around 3 gallons will be changed, sorry if this sounds like a stupid question normally I just get handed the right amount of salt and I am wanting to do it myself instead, I use marine salt (which only does me around 20 gallons but costs me 16.28 dollars). I'm getting a refractometer soon instead of that no good hydrometer! Thanks in advance!

[Fishguy2727]

Why do you want it that low?

[Cleggat]

It's for a young puffer fish.