bought a used refractometer (D&D)for about a year ago. Even though I calibrate it with a calibration solution, suddenly the refractometer is no longer calibrated. What do people recommend buying now? digital? refractometer?
The tropic marin hydrometer. Can't get more accurate than that. The only correction to make is for temp, it's calibrated for 77 degrees and since my tank runs 78 the correction is negligible. Absolutely love this and use it to calibrate my refractometer as well.