Refractometer Standard

[lattehiatus]

pH calibration standards have ~90 days of opened bottle shelf life and ~2 years unopened, but they do very from standard to standard ( IE. higher ones IIRC have less of a shelf life due to CO2).

We make our own here at RMI and we only do it like once a year given the shelf life.

Thanks for the info! I remember using borax to make a pH standard in a pinch way back in the day, and my laundry reaped the benefit of having a box of 20 Mule Team on hand.

The label on the standard says something like "1.026 or 35 ppm" (Or whatever, I don't have it here).

I went to calibrate my refractometer and noticed that my 1.026 does not match up with the 35ppm (or whatever)!!

So I'm thinking ... Ugh, I guess just pick one or the other! So I chose 1.026.

Chalk that one up to rounding error - sorry! At 25C, 35 ppt correlates to 1.0264 sg.

 

[BAYMAC]

We don't use Borax, that I can say Our standards are just like you'd buy, same colors even.

Borax is awesome to keep around though, so many uses