I used to keep my tank at 1.020 to 1.021.
Found that this is a good figure for my tank as i dont need to use too much salt(i used 1 bucket of 23kg every mth)
Easier to settle down new fishes,
Able to hold colour, for people who seen my tank last time, my queen was able to hold the blue, (partly it was a belize queen so easier to hold)