Refractometer accurate? If you missed this thread you may want to read it.

[lllosingit]

Here is the thread titled My refractometer is way off when testing with Pinpoint 53mS calibration fluid

smj877 found his blue RHS 10-ATC way off when calibrating with RO water.
He bought Pinpoint 53mS salinity calibration fluid to double check and found it was off by .004!
Now it has me wondering if mine is accurate or not.

<a href=showthread.php?s=&postid=8368143#post8368143 target=_blank>Originally posted</a> by sjm817
I got some Pinpoint 53mS salinity calibration fluid and tested my blue RHS 10-ATC (the cheap one everyone has) refractometer. It measured 1.030!!

The Pinpoint conversion chart shows it should read 1.0259, which is what I expect a calibration fluid would be set for. Now, if I check with plain RO, it does not measure 0, but is way below the scale.

I assume I should believe this calibration fluid?