Refractometer / Hydrometer question - Page 2

HankB · 03/26/2008, 02:36 PM

Quote:

Originally posted by Randy Holmes-Farley
You often cannot use the same hydrometers or refractometers for beer and tank water. Beer is lower in sg than freshwater, while seawater is higher than freshwater.

My first use of refractomerers was in a hospital lab where it was use to measure the specific gravity of urine. That would probably work better than the one intended for beer.

And I sure wouldn't want to mix them up!!!

Aquarist007 · 03/26/2008, 04:29 PM

Quote:

Originally posted by HankB
My first use of refractomerers was in a hospital lab where it was use to measure the specific gravity of urine. That would probably work better than the one intended for beer.

And I sure wouldn't want to mix them up!!!

would be easy to mix them up if you were using it for urine and the salinity of the tank

In case you were missed

To Reef Central

fareforce · 03/26/2008, 06:22 PM

Quote:

Originally posted by capn_hylinur
would be easy to mix them up if you were using it for urine and the salinity of the tank

In case you were missed

To Reef Central

I think mixing up the urine, and beer one would be worse..

Randy Holmes-Farley · 03/27/2008, 07:39 AM

My first use of refractomerers was in a hospital lab where it was use to measure the specific gravity of urine. That would probably work better than the one intended for beer.

And I sure wouldn't want to mix them up!!!

And just to be clear, that type is especially inappropriate to use for a reef tanks, even though it reads in sg, that is for proteins, not salts:

http://reefkeeping.com/issues/2006-12/rhf/index.php#16

Clinical Refractometers

--------------------------------------------------------------------------------

Some medical and veterinary labs use a type of refractometer called a "clinical refractometer." These are normally used to measure proteins in urine, serum and other biological fluids. The scale can read in units familiar to reef aquarists (ppt or specific gravity), but that is ppt or specific gravity of a protein solution, not a seawater solution. Those units should be ignored, and if they are all that is available on the refractometer, I'd find another refractometer. Without a conversion table to seawater salinity or specific gravity, such readings cannot be used to gauge seawater's salinity as they will be way off. Some clinical refractometers read in refractive index, which is okay if you match the refractive index to the appropriate seawater refractive index (e.g., 35 ppt seawater has a refractive index of 1.33940). Such conversions of refractive index to salinity or specific gravity are shown in Figures 1 and 2, and Table 1.

HankB · 03/27/2008, 11:35 AM

Quote:

Originally posted by Randy Holmes-Farley
...

And just to be clear, that type is especially inappropriate to use for a reef tanks, even though it reads in sg, that is for proteins, not salts

I'm glad you mentioned that and have to admit to being surprised. Ordinarily urine should not include proteins. I thought the major contribution to SG would be salts of various kinds. Of course, for clinical purposes differences as small as 0.001 are insignificant so the calibration might not be as accurate either.

-hank

Aquarist007 · 03/27/2008, 02:07 PM

when you rely so much on the accuracy of salinity then you should buy the proper refractometer for measuring salinity and the proper pinpoint standardizing solution.

fareforce · 03/27/2008, 02:24 PM

With the pinpoint solution, do you put it on the refractometer, and calibrate to zero, or is to a specific number?

Aquarist007 · 03/27/2008, 04:03 PM

Quote:

Originally posted by fareforce
With the pinpoint solution, do you put it on the refractometer, and calibrate to zero, or is to a specific number?

you put it on the refractometer and calibrate it to 35

Aquarist007 · 03/27/2008, 04:08 PM

how to calibrate a refractometer--tips right from king neptune

http://reefkeeping.com/issues/2006-12/rhf/index.php#20

fareforce · 03/27/2008, 04:19 PM

Quote:

Originally posted by capn_hylinur
how to calibrate a refractometer--tips right from king neptune

http://reefkeeping.com/issues/2006-12/rhf/index.php#20

Thank you!!!

HankB · 03/27/2008, 08:14 PM

Quote:

Originally posted by capn_hylinur
when you rely so much on the accuracy of salinity then you should buy the proper refractometer for measuring salinity and the proper pinpoint standardizing solution.

I will and I did and I did.

Thanks for posting the link to the article on refractometers.

-hank

Aquarist007 · 03/27/2008, 09:37 PM

Quote:

Originally posted by HankB
I will and I did and I did.

Thanks for posting the link to the article on refractometers.

-hank

your welcome and happy reefing

03/27/2008, 07:39 AM	#29
Randy Holmes-Farley Reef Chemist Join Date: Apr 2001 Location: Arlington, Massachusetts Posts: 86,233	My first use of refractomerers was in a hospital lab where it was use to measure the specific gravity of urine. That would probably work better than the one intended for beer. And I sure wouldn't want to mix them up!!! And just to be clear, that type is especially inappropriate to use for a reef tanks, even though it reads in sg, that is for proteins, not salts: http://reefkeeping.com/issues/2006-12/rhf/index.php#16 Clinical Refractometers -------------------------------------------------------------------------------- Some medical and veterinary labs use a type of refractometer called a "clinical refractometer." These are normally used to measure proteins in urine, serum and other biological fluids. The scale can read in units familiar to reef aquarists (ppt or specific gravity), but that is ppt or specific gravity of a protein solution, not a seawater solution. Those units should be ignored, and if they are all that is available on the refractometer, I'd find another refractometer. Without a conversion table to seawater salinity or specific gravity, such readings cannot be used to gauge seawater's salinity as they will be way off. Some clinical refractometers read in refractive index, which is okay if you match the refractive index to the appropriate seawater refractive index (e.g., 35 ppt seawater has a refractive index of 1.33940). Such conversions of refractive index to salinity or specific gravity are shown in Figures 1 and 2, and Table 1. __________________ Randy Holmes-Farley Current Tank Info: 120 mixed reef

03/27/2008, 02:07 PM	#31
Aquarist007 Registered Member Join Date: Apr 2007 Location: Hamilton, Canada Posts: 28,240 Blog Entries: 1	when you rely so much on the accuracy of salinity then you should buy the proper refractometer for measuring salinity and the proper pinpoint standardizing solution. __________________ I prefer my substrates stirred but not shaken Current Tank Info: 150gal long mixed reef, 90gal sump, 60 gal refugium with 200 lbs live rock

03/27/2008, 02:24 PM	#32
fareforce Premium Member Join Date: Feb 2005 Location: Anchorage, AK (Alaska) Home of the frozen weasel Posts: 1,811	With the pinpoint solution, do you put it on the refractometer, and calibrate to zero, or is to a specific number? __________________ It's not my fault!!! It was an I.D.ten.T. thing.. Gosh!!!! (ID10T) --------------------------------------------- Click the red house to see my current build thread! Current Tank Info: Current Project. 110 gallon starphire.

03/27/2008, 04:08 PM	#34
Aquarist007 Registered Member Join Date: Apr 2007 Location: Hamilton, Canada Posts: 28,240 Blog Entries: 1	how to calibrate a refractometer--tips right from king neptune http://reefkeeping.com/issues/2006-12/rhf/index.php#20 __________________ I prefer my substrates stirred but not shaken Current Tank Info: 150gal long mixed reef, 90gal sump, 60 gal refugium with 200 lbs live rock