As an engineer, I thrive on data. So until now I have relied upon my hydrometer, refractometer and Tilt to deliver the Specific Gravity readings on which I rely. When I first received my hydrometer - it was a gift - I checked in some water and it read 1.000, as expected. Or, at least I think I did... After a few brews, I spent <$20 on The Amazon and got a cheap refractometer. It, too read 1.000 with water; of this I am sure. A few brews after that, I splurged on a Tilt. The idea of monitoring a fermentation in real time, as opposed to periodic 8 oz samples, was very seductive. Indeed, watching the fermentation is almost the highlight of my day, when something is fermenting. The Tilt reads 1.000 or 0.999 in water from the tap. The problem is none of them ever agree. I get three different answers every single time, and this is very frustrating to me. Last brew, the OG was 1.059 on the hydrometer, 1.058 on the refractometer, and 1.057 on the tilt. No, not a big difference, but... FG for that beer was 1.022 on the hydrometer and 1.011 on the tilt. Waugh! What to believe? (Oh, and all are at 60-65 F, I do check the temperature). Checking the hydrometer, I got what you see in the photo (1.004 to my eyes) in tap water at 60 F. (It is a 60 F hydrometer). How can this be? Do I just have a cheap instrument, and simply need to spend more to buy a better one? I checked for bubbles in the water, found none. I have half a mind to visit the FLHBS and compare all of their stock to mine. I also wouldn't mind spending $40 on a good hydrometer, but the one I have is a USA-made BSG, I'd expect it to be spot on. Even though it was maybe $10. /Rant What I plan to do is get some distilled water and create two different sucrose solutions and check the calibration at all three points of all three instruments. Create correction tables for each, and use them every time. But I am open to other suggestions. Does anyone have a story of similar experiences? Perhaps with an action plan? Or am I just too worried about 8 thousandths of a gravity point?