Ok so typically with most refractometers you have SG running down the left side of the scale when you look through, and salinity running down the right.
You should not be getting a reading of "4" that would mean you hardly. Test it with RODI water or bottled water would work and make sure that the reading is either 1.000 SG or 0 salinity. If it isn't use the little screwdriver to move the blue line to that mark. Then do your test making sure you have enough water in the "chamber" and the lid is down tight enough that the water covers the blue grid of the chamber.
Not sure about multiplying by 4. Never heard of that.
Hope this helps
