Refractometer Calibration mentioned at meeting

[mike1962]

Hi All,

Someone mentioned at last nights meeting in the advanced/intermediate side that there was an article on Refractometer Calibration, and that standard calibration with RO on cheaper Refractometers caused them to be off. I didn't catch which article it was and would like to read it since I have one the those 'cheaper' refractometers and unfortunately have used RODI to calibrate it. I've always been a little suspect about how truly calibrated it was. So if any of you could point me in the direction of the article that would be great.

Since I'm on the topic, I was wondering if any of you have gone from a cheaper model refractometer to a more professional version and if you found it to be of greater accuracy. One complaint that I have about mine (the Marine Depot special) is that the lines of gradation are so close to one another I am often wondering just how precise I am reading it.

 

[airinhere]

These may help. First one is Reef Aquarium Salinity, Homemade calibration standards. And the second is Refractometers and Salinity Measurements.

http://reefkeeping.com/issues/2004-06/rhf/index.php

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

Sounds like you have already figured out part of why there are more expensive versions around. Some also have lights, are temperature adjusting etc... Some people get one and never have to recalibrate again, others with the same model have to recheck their calibration often. More expensive models are supposed to be better made and thus, remain accurate.

Everyone should check their calibration from time to time.

 

[tfp]

here's the thread i originally came across. there should be a bottle of the pinpoint calibration fluid floating around the club.

http://reefcentral.com/forums/showthread.php?threadid=953605&perpage=25&pagenumber=9

hth,
tim

 

[mike1962]

Thanks Guys,

This helps!

Regards,

Michael

 

[kdblove_99]

Looks like i have the cheap blue handled refractometer like most in the thread Tim posted.

I will buy 2 bottles of the solution amd donate one to MARS at next meeting and everyone can bring in there refracs and test them

Tim,

IS this the stuff?
http://www.premiumaquatics.com/Merc...ROD&Product_Code=PIN-SAL-FLUID&Category_Code=

 

[tfp]

kdblove, that would be the stuff .

 

[kdblove_99]

STuff came today looks like my refrac was off 0.03

So it was reading 1.023 when it should have been 1.026. Fixed now.

SO next meeting i will have the extra bottle i will donate to the club