Digital Measure vs refractometer

[Fulinn]

Hi,

I have a Digi-Specific Gravity measuring devise as well as having a refractometer.

I assumed ( this maybe my error ! ) that the digital measure of the SG would be the most accurate.

So I've been measuring my SG faithfully with my digital devise and getting 1.021 as the result, which is lower than what I wanted, so I've been gradually raising the salinity of the water looking to get to 1.025.

Tonight I measured digital = 1.023 and then gave the refractometer a try just to verify the results and got 1.031 which is way to high !!

So which is the most accurate ?

Thanks !

Bonnie

 

[Anonymous]

I have a digital tester. It lives in a box because its not all that accurate, and I cant bring myself to sell it to someone else because I would feel bad about that.

 

[Len]

The refractometer, calibrated, is more accurate. Digital salinity meters, especially cheap ones, are prone to interference.

 

[Anonymous]

Yes, surprising but true, digitals aren't as reliable as good old opticals

 

[Anonymous]

Agree with all above. Love my refractometer.

 

[bleedingthought]

Count me in, I dig my refracto.

 

[Anonymous]

hobby-grade SG or conductivity meter is not that good. You need to get a decent unit, but most will cost you a few hundred dollar. In either case, if you have regular calibration, you should be pretty good. For refracto, all you need to do is use tap water to recalibrate. For the electronic ones, you need to have two NIST-certified (or equiv.) solutions.

 

[Fulinn]

Thanks All,

Well, I guess that's 60.00 down the drain. Drats !!! cause it was very easy to use.

Back to the refrac, sure glad I had one already !


Bonnie

 

[Anonymous]

Well, as I said, you just need to recal it periodically. It is a good tool if you need to take dozens of measurements. Just dip, take the value, wash the probe, and repeat. But for most people who only need to check the SG once a while, refractometer is better choice.