How to calibrate refractometer?

t5Nitro · 10/06/2009, 03:19 PM

I've been calibrating my refractometer with distilled water.

Most likely it's off so I want to get some of this:

http://www.drsfostersmith.com/produc...m?pcatid=18717

When I place that on it and read it, where does it need to be? 1.025?

thegrun · 10/06/2009, 03:27 PM

1.0264 = 35ppt

romanr · 10/06/2009, 04:12 PM

I was calibrating with distilled also and when I got the salinity reference it showed it was off a bit. I no longer calibrate with distilled water.

Blownsvt · 10/06/2009, 04:31 PM

hmm. i calibrated mine with RO/DI water figured if the salinity of that is 0.00 it should work just fine since thats what i am adding the salt to.

JAustin · 10/06/2009, 05:49 PM

If you do not callibrate with 1.0264 = 35ppt solution you will be off slightley.

t5Nitro · 10/09/2009, 06:01 PM

Yea, I picked up some calibration solution and instead of being 1.025 it was at 1.024. Not too much off, but at least now it's accurate. I was using distilled water before.

Randy Holmes-Farley · 10/09/2009, 06:20 PM

I explain why these refractometers are off when calibrated with fresh water here. In short, they are not made for seawater but for pure sodium chloride solutions:

Refractometers and Salinity Measurement
http://reefkeeping.com/issues/2006-12/rhf/index.php

10/06/2009, 03:19 PM	#1
t5Nitro Registered Member Join Date: Aug 2006 Location: Wisconsin Posts: 4,384	How to calibrate refractometer? I've been calibrating my refractometer with distilled water. Most likely it's off so I want to get some of this: http://www.drsfostersmith.com/produc...m?pcatid=18717 When I place that on it and read it, where does it need to be? 1.025? __________________ ATI T5 club Current Tank Info: Left the hobby, looking to re-enter in the future

10/06/2009, 04:12 PM	#3
romanr Registered Member Join Date: Jul 2005 Location: Ocala, Florida Posts: 1,568	I was calibrating with distilled also and when I got the salinity reference it showed it was off a bit. I no longer calibrate with distilled water. __________________ Raul Roman Marion Ocala Reef Enthusiasts (MORE) member Check us out on FB and RC. Current Tank Info: 150 DD cube mixed reef, 30G sump, Eshopps S-150 cone skimmer, 400W Radium MH, 156W Wavepoint T5, Internet accessible ACIII controller , Vortech MP10 w/ Icecap battery backup, Mini-Arctica chiller, Katalyst fueled reactor fed to Octopus BH800S skimmer

10/09/2009, 06:01 PM	#6
t5Nitro Registered Member Join Date: Aug 2006 Location: Wisconsin Posts: 4,384	Yea, I picked up some calibration solution and instead of being 1.025 it was at 1.024. Not too much off, but at least now it's accurate. I was using distilled water before. __________________ ATI T5 club Current Tank Info: Left the hobby, looking to re-enter in the future

10/09/2009, 06:20 PM	#7
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	I explain why these refractometers are off when calibrated with fresh water here. In short, they are not made for seawater but for pure sodium chloride solutions: Refractometers and Salinity Measurement http://reefkeeping.com/issues/2006-12/rhf/index.php __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

10/06/2009, 03:27 PM	#2
thegrun Registered Member Join Date: Dec 2008 Location: Garden Grove, Ca Posts: 17,023	1.0264 = 35ppt

10/06/2009, 04:31 PM	#4
Blownsvt Moved On Join Date: Sep 2009 Location: Minnesota Posts: 514	hmm. i calibrated mine with RO/DI water figured if the salinity of that is 0.00 it should work just fine since thats what i am adding the salt to.

10/06/2009, 05:49 PM	#5
JAustin Acropora Nut Join Date: Jul 2008 Location: Oklahoma City Posts: 1,628	If you do not callibrate with 1.0264 = 35ppt solution you will be off slightley.