What is the most accurate refractometer to buy (without spending an insane amount of $$$)

[tannersmith200]

I bought a refractometer for $50 dollars and thought it was going to be pretty accurate and I know its not that accurate. It's probably .003-.004 off.
It says to calibrate it with distilled water however I am a little skeptical with this method.
Does anyone have any suggestions???
Thanks

 

[meowzer]

Yeah....calibrate it with distilled water.......LOL
Mine came with its own water, but when I run out I will just buy a bottle of water....

 

[mproctor4]

Your distilled water should be the same temperature as your tank water. I struggled with that and then started putting distilled water in a ziplock baggie (actually double bagged it so no leaks) and float it in my sump so I know the temp. is the same when I want to calibrate it.

 

[tannersmith200]

Oh ok.
I have been using my RODI water bec of its quality but I will try bottled water at the same temp as my tanks.
Thanks you all!

 

[acrylic51]

Most refractometers have ATC, so shouldn't worry to much about matching temp.

 

[aquaknight]

Your refractometer is off by.003/.004, of what, your LFS's refracto? Your hydrometer? You've calibrated it with RODI (that's what I use) to 1.000 and it's still off by .003 when reading tank water? Is it always off by the same amount, or is it randomly off?
Make sure your lens and the clear plastic cover are completely clean and there aren't any scratches on either. As acrylic stated, I've don't think I've seen a refractometer sold that doesn't have ATC.

 

[tannersmith200]

ATC = Automatic temp correction??? I am guessing???

 

[acrylic51]

Correct. A quick question to the OP, what were you using as a reference to compare the accuracy of the refractometer against?

 

[tannersmith200]

Quote:
Originally Posted by acrylic51 http:///forum/thread/383446/what-is-the-most-accurate-refractometer-to-buy-without-spending-an-insane-amount-of#post_3354049
Correct. A quick question to the OP, what were you using as a reference to compare the accuracy of the refractometer against?
I have an aqua controller 3 pro with a conductivity probe (lab grade)
It's very accurate so that is how I am comparing parameters. I have pH, ORP, Temp, and Conductivity probes.
But I have three tanks along with two QT tanks so checking parameters regulary is a must.

 

[acrylic51]

True the Aquacontroller monitors alot of parameters, but you can't monitor salinity with it, so you can't be using that to judge the accuracy of your refractometer.

 

[tannersmith200]

Quote:
Originally Posted by acrylic51 http:///forum/thread/383446/what-is-the-most-accurate-refractometer-to-buy-without-spending-an-insane-amount-of#post_3354404
True the Aquacontroller monitors alot of parameters, but you can't monitor salinity with it, so you can't be using that to judge the accuracy of your refractometer.
conductivity does translate to salinity with a little math lesson.

 

[acrylic51]

The AquaController III with conductivity probe isn't cheap and most won't shell out the cash, so the original question was the most reliable; cost effective way would still be a refractometer....Why do I want to sit or anyone else want to sit and do a math equation, when you can just pull out the refractometer and get an immediate reading???