I've come to the conclusion that my hydrometer is off by a couple of points, so want to figure out how to be more accurate with what I have (i.e. I'm not going to shell out for a $75 pro set)
1. Everything I've come across for calibrating your hydrometer suggests to calibrate it using distilled water at the appropriate temperature. This doesn't seem right to me. I don't brew with distilled water. I brew with my tap water and want to know how much sugar is in it, right? So it seems I should use my tap water as the zeroing standard.
2. If my hydrometer is floating high, say by 2 points. Is it valid to simply weight it slightly (i.e. by adding a couple of pieces of tape, a piece of clay, whatever) to zero it in my calibration fluid?