Refracto Meter

Luke.

Distinguished Member
Joined
Jun 9, 2015
Location
Kitchener
So how do you adjust to re calibrate ? It said a solution would this work ? Came in a alk test kit (probably not lol)
How do you guys do it ?
image.jpg
 

Nighthawk26

Active Member
Joined
Apr 10, 2015
Location
Waterloo
Fauna Marin has the most appropriate calibration solution from everything I have read and understood. That said, EVERYONE has an opinion on it, but my Red Sea says to calibrate with DI water, and I do. I have tested it against the other methods and it holds true. Not all refractometers are the same so it`s important to follow the manufacturer instructions or know if it`s base has been calibrated for Brine, and if it is ATC for example. The Red sea is both ATC to 25 degrees, and also for sea water specifically.
 

heath

Distinguished Member
Joined
Oct 2, 2012
Location
Woodstock, Ontario
not sure if that will work, there should of been a bottle that came with the refractormeter...its called refractormeter calibration solution...if you were closer I have an extra bottle here..
 

Pipes

Active Member
Joined
May 21, 2015
Location
Ingersoll
I have 2 somewhere (in storage) and the new one didn't have calibration fluid. Hmmm. Maybe I got ripped...
 

heath

Distinguished Member
Joined
Oct 2, 2012
Location
Woodstock, Ontario
mine WAS a vertex too...:(
the bottle that I have must have been purchased later, its from a different company and the price tag says..12.99...expensive stuff, 2 oz...
 

Pistol

Super Active Member
Donor
Joined
Aug 16, 2012
Location
Corunna
RODI at 0 tds will read 0 salinity, you can't always trust calibration fluid, I've had a couple bad bottles. The companies that the stuff don't care if it's accurate they just want your money.
 

zoomster

Active Member
Joined
Jan 2, 2014
Location
Port Rowan, Ontario
I actually do both.
I test with DI, then calibration fluid at 35PPT.
Adjust to 35PPT then do both steps again.
If I get the 0 and 35 respectively the second time, I am satisfied.
Is this good??? :)
 

Pistol

Super Active Member
Donor
Joined
Aug 16, 2012
Location
Corunna
IMO, you should always calibrate using a solution as close as possible to the solution you are measuring because of what Randy Farley-Holmes refers to as the slope mis-calibration that can occur. See his article here for everything you might want to know about calibrating a refractometer and more.

http://reefkeeping.com/issues/2006-12/rhf/

Dan
The calibration fluids sold to us in this hobby are not accurate enough, it's like measuring .001" with a yard stick, I've done a lot of testing on this myself and the fact is that the calibration solutions are a waste of money, I know, I wasted about $50 on them. RODI at 0 tds is the way to go.
 

EricTMah

Aquariums by Design
Joined
Mar 2, 2014
Location
Kitchener, Ontario
Website
www.aquariumsbydesign.ca
The calibration fluids sold to us in this hobby are not accurate enough, it's like measuring .001" with a yard stick, I've done a lot of testing on this myself and the fact is that the calibration solutions are a waste of money, I know, I wasted about $50 on them. RODI at 0 tds is the way to go.
Completely agree.
I make my own

Sony Xperia Z3
 

Dan Cole

New Member
Joined
Jun 26, 2016
Location
Hamilton, ON
I actually do both.
I test with DI, then calibration fluid at 35PPT.
Adjust to 35PPT then do both steps again.
If I get the 0 and 35 respectively the second time, I am satisfied.
Is this good??? :)

That's an excellent practice....as Regan said...."trust but verify".
 
Last edited:

Dan Cole

New Member
Joined
Jun 26, 2016
Location
Hamilton, ON
The calibration fluids sold to us in this hobby are not accurate enough, it's like measuring .001" with a yard stick, I've done a lot of testing on this myself and the fact is that the calibration solutions are a waste of money, I know, I wasted about $50 on them. RODI at 0 tds is the way to go.

My experience is different but I agree that you should always double check your results. I've seen a lot of people in this hobby making changes based on bad information. Please also keep in mind that most TDS meters are plus/minus 2% when it comes to their accuracy and when calibrated to zero the slope mis-calibration can result in your being a long way off. That is the reason it is recommended that you calibrate based on a solution in the range you are testing. Whether you should trust the solutions sold in the industry "trust but verify" is a good rule to follow. I don't think the manufacturers are out to screw you but lets face it, people make mistakes.
 
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