I tested the SG/Salinity of the new tank and to my surprise it was WAY under, 1.005! so i dosed the marine salt again, this time adding 400grams and mixing it into the tank directly. I waited a few more hours and tested the SG/Salinity again with my refractometer and it sat around 1.013 - 1.014 so i will leave the tank for a few days and retest. If the salinity is sat on 1.013 then i wont touch the water further, anything over and i will add some pure RO to bring the salinity down a little.
Here is a bad shot of my meter looking through the refractometer, sorry for the quality its so hard lining up a phone camera down a scope making sure enough light is coming in to show the result
Its pretty clear in real life situations.
I also added one small scoop of matured crushed coral from one of my other tanks to seed the new one, this will reduce the cycle time dramatically.
Note: the tank has had 730grams of Instant ocean salt all together.