Refractometers are much more reliable and accurate. There is a tube with a round part at the end, similar to a tiny turkey baster. You place the end of that into the water and squeeze the ball part. Then open the flap on the refractometer. Squeeze the liquid onto the lens, close the flap, and look toward a light. You may have to buy one that needs to be calibrated. To do that, do the same thing, but use RO water. Turn the knob until the SG and salinity read zero (they are across from each other). The eye piece can also be adjusted to suit your eye sight.