refractometer calibration
 

I've always calibrated my refractometer using plan old RO water and although I knew some error would be involved I was under the impression the amount would be so small it would not make a difference. However I keep hearing more and more lately people stating after reading a few articles that this isn't the case and you need to calibrate your refractometer with some kind of calibration fluid otherwise you'll be off a noticeable amount.

Just wanted to share that after receiving some PINPOINT Salinity Calibration Fluid to calibrate my conductivity probe I stuck some in my refractometer and it's it reads exactly 1.026 as it should, not even out the slightest bit as far I can tell.

So regardless what articles my suggest it seems I can conclude that RO water is certainly an acceptable calibration solution. Anyone else try this and get similar or different results?

Yes, my refractometer came with 18 megaohm water(pure) for calibrating at 0, I compared that to my RODI and it was the same, I bought calibration fluid after reading (probably the same) an article and checked the calibration and yes it was correct. All 3 gave the same results, so now I can use my RODI water to check my calibration fluid.:crazy:

What is calibration fluid? Sounds like RO water in a fancy container with a pretty label for a stupid amount of $$$. Somebody always out to make a buck...lol Good to know this has been double checked, I always use RO water to check mine. Thanks for posting....:biggrin:

most LFS will calibrate for you.. Or so I have heard... mines over due to be calibrated, I'm sure my salinity is off by now

Why bother? You got RO water?

yeah, not great RO though I dont trust it to be as accurate

This is a point of the thread to eliminate the myths involved with refractometer calibration. Straight tap water reads zero on my refractometer, which was just proven accurate.

really?
but water quality varies where ever you go, so personally wouldn't use tap water for my refractometer
especially considering the poor water quality we have in Wetaskiwin

The refractometer is for salinity. Try it and see what it says then compare to you RO, if the numbers are the same, then I would say either is fine for calibrating it. If you get different numbers then just use your ro.

It should be able to test for both salinity & specific gravity.
I believe that the proper water temp should also be part of the equation for calibrating. Please correct me if I am wrong.