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snapperface
10/07/2008, 04:23 PM
Salinity Refractometer can u use ro/di water to calibrate it. or do u need to buy Calibration fluid? An ebay seller says all u need is ro/di water to calibrate the refractometer i just want to comfirm is this true?

thanks

Kieth71
10/07/2008, 04:33 PM
I did the same thing when i first got mine using ro/di water.I bought some pinpoint salinity calibration fluid when i was at the lfs recently and it was off a bit.I believe randy has a recipie for making your own as well if you want to go that route.

snapperface
10/07/2008, 04:44 PM
so how many people out there use only ro/di water

Rysam
10/07/2008, 05:07 PM
RO will not give an accurate calibration, even though the seller/instructions say its good. you NEED the solution for accuracy. for 5 bucks it will last a lifetime of calibration and you will know its right.

Saltcity
10/08/2008, 04:17 PM
My instructions say to use Distilled water....

I've checked mine with a Hydrometer And the Refractometer and its the same with either...

mg426
10/08/2008, 04:36 PM
Here is the deal. You must calibrate and verify that the instrument is accurate at the range it is being asked to measure. Who really cares if it will measure RO/DI water accurately. It other words most instruments have a Zero and a Span. Zero is a reference point for the bottom end only! The Span reading in this case 1.026 (using Pinpoint calibation solution) is the range or very near the range that we as hobbyists are aiming for.

Saltcity
10/08/2008, 04:39 PM
<a href=showthread.php?s=&postid=13509495#post13509495 target=_blank>Originally posted</a> by mg426
Here is the deal. You must calibrate and verify that the instrument is accurate at the range it is being asked to measure. Who really cares if it will measure RO/DI water accurately. It other words most instruments have a Zero and a Span. Zero is a reference point for the bottom end only! The Span reading in this case 1.026 (using Pinpoint calibation solution) is the range or very near the range that we as hobbyists are aiming for.

Why would it tell me to use distilled..... stupid Refractometer people!:hammer:

mg426
10/08/2008, 04:48 PM
I cant speak for the refacto people. I just know that you need to use the cal. solution. Myself I would trust a swingarm hydrometer that has been verified with a cal. solution more than I would a refactometer verified @ zero with just RO/DI water.