I have had the Milwaukee unit for a year or so. I loved it at first, but the readings started to get inconsistent when compared to a calibration solution or a calibrated refractometer. I ended up getting TM hydrometer, and so far I trust it. But a couple weeks ago I tried the Milwaukee again. It read about 1.022 with the 1.025 calibration fluid after calibrating it with steam distilled water. Even though it did not indicate that the battery was low, I changed out the battery, and now it is pretty much spot on with the calibration fluid. So if your Milwaukee readings seem off, try swapping out the battery with a new one. And also make sure you are filling the little dish completely with sample water, and give it a little time to acclimate temperature.