2 tbsp/g probably won't even register on a hydrometer (which you need to measure salinity). To get a SG of 1.005, it takes roughly around 1 cup of salt/5g. 1.014 is pretty good for an adult GSP but just a little higher & you can convert it to SW & add live rock/sand & a protein skimmer, reducing the need for so many large, weekly water changes.
And yes I know that's very little salt, I'm raising it slowly so I don't kill the beneficial bacteria all at once. I also do have a hydrometer but it only goes down to 1.010