I'm using two hydrometers and a refractometer and I can't get over the wide spread in range between all three. I'm going with the refractometer which is showing 1.026 while the hydrometers are reading 1.021 and 1.023 respectively. i feel safer with the refractometer since I've calibrated both with the Calibration solution and R/O water. Ive gone ahead and ordered a salt water specific hydrometer which should arrive Thursday. I'm just a little over cautious?