Refractometer help

Reefer07 · 01/03/2009, 12:34 AM

Today I got a Milwaukee refractometer. I calibrated it by following the directions. I measured my tank at 1.030!!
Now I have always measured with a hydrometer but I have checked it with a friends refractometer. Now I have no problems in my tank or at least nothing appears to look bad. I have a 29g mixed reef with some SPS that are thriving.
My question is what are the chances of my SG being really 1.030? Whatever they are it's always been constant.
On the hydrometer I always mixed my salt to 1.025 and I have always measure it from my tank as 1.025.

I am thinking I calibrated it wrong some how. Is there any way the refractometer could be damaged or as long as it's calibrated properly it works?

Thanks for any help,
Zac

AusWog · 01/03/2009, 02:44 AM

im having the exact same problem, identical my salinty is 1.030 on my refracto and 1.026 on my hydrometer, im thinking the hydrometer is out of wack and old ive been told some only last 6 months some times.is it ok to use tap water to calibrate the refracto or does it have to be distilled water?

Reefer07 · 01/03/2009, 09:27 AM

Either way I find it hard to believe everything is doing perfectly well but my SG is at 1.029-1.030.
I tested my bucket of salt I use for W/C and it measured the exact same.
The only thing I am concerned about is it talked about the temp. and said the prism has to match the sample temp. etc. etc.
How does one achieve this? Or maybe no one does this at all.

Eldredge · 01/03/2009, 09:37 AM

It is best to calibrate your refractometer with a calibration solution that is the correct salinity (like PINPOINT calibration fluid). It is not unusual for a refractometer to be accurate at 0 (distilled water), but way off at 35 (correct salinity). As far as temperature, the only thing I would think of is to allow time for the tem to equalize. Mine compensates for temp, so I don't know for sure.

qfrisco · 01/03/2009, 12:53 PM

Not sure which model Milwaukee you have, but I have a Milwaukee ATC100. The instructions call for using distilled water to calibrate to 1.000. However, calibrating with the Pinpoint solution (which comes standard at 1.0264) showed that the distilled water calibration was 0.002 off.

If this same thing is happening in your situation, your actual SG is really 1.028, still high, but not AS high.

Either way, the key to everything is stability. As long as your livestock eased into 1.028, they should be fine. Also goes to show just how resilient these creatures are!

Reefer07 · 01/03/2009, 11:39 PM

1.000? I put some distilled water in and turned the screw until it was on the 0 line exactly on the right side.
So say it is really 1.028ish....as I slowly bring it down to .025 when it reaches 1.025 am I going to see any better growth/coloration in my corals possibly?

Ebmorri · 01/03/2009, 11:45 PM

Heres a read on calibrating Refractometers

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

qfrisco · 01/04/2009, 09:25 AM

Quote:

Originally posted by Reefer07
1.000? I put some distilled water in and turned the screw until it was on the 0 line exactly on the right side.
So say it is really 1.028ish....as I slowly bring it down to .025 when it reaches 1.025 am I going to see any better growth/coloration in my corals possibly?

On my Milwaukee, the scale reads Specific Gravity on one side and Salinity on the other. Either way, if you're calibrating with distilled water, you want to turn the screw until the meter reads 0 Salinity which is the equivalent of 1.0000 Specific Gravity.

Not sure if you'll see better growth. My experience is that corals prefer "thicker" water, which is why I like to keep my water at 1.026, but I guess it's possible you'll see better color and growth.

With your 29 gallon tank, you just need to take about 1.5-2 gallons out and replace with fresh RO/DI water to get an SG of 1.026 - assuming your tank volume is closer to 26 gallons with live rock displacement, etc.

Reefer07 · 01/04/2009, 06:43 PM

Thanks for the help qfrisco and the link ebomarri.
Frisco you got it right that my tank is about 26g + a 10g sump with probably 6ish gallons of water in it.

CheckitOut · 01/05/2009, 02:27 PM

I also rescently bought a Milwaukee refractometer, and my question is do I adjust to the solution that I bought or do adjust it to distilled water, which method is better?

qfrisco · 01/05/2009, 02:55 PM

Quote:

Originally posted by CheckitOut
I also rescently bought a Milwaukee refractometer, and my question is do I adjust to the solution that I bought or do adjust it to distilled water, which method is better?

It's best to adjust with the solution you bought (assuming it is the Pinpoint 53.0 mS Salinity calibration fluid or equivalent).

In my post above, I described how I first calibrated with distilled (as called for in the Milwaukee instructions). But then calibrating with the Pinpoint solution showed that the calibration with distilled was 0.002 off. Using distilled calibrates your meter for use in the 1.000 Specific Gravity range, which is not where our saltwater is. Using the Pinpoint solution calibrates your meter for use in the 1.026 range, which is where you want your water to be.

Hope that makes sense. :-)

SHOmuchFUN · 01/05/2009, 03:14 PM

I just got a refracto for my tank and found my salinity to be 1.030 as well.

Swing-arm hydrometers are NOT accurate, but I had been using them for years. Near as I can figure, my tank had just become accustomed to the higher specific gravity. An evolution of sorts. I am gradually watering down my water changes and occasionally scoop out a liter or two of water and let the topoff do its thing.

I'm not surprised as to your reading and doubt it's because your refracto is not calibrated. They typically come calibrated from the factory.

01/03/2009, 12:34 AM	#1
Reefer07 Registered Member Join Date: Aug 2007 Location: Connecticut Posts: 2,090	Refractometer help Today I got a Milwaukee refractometer. I calibrated it by following the directions. I measured my tank at 1.030!! Now I have always measured with a hydrometer but I have checked it with a friends refractometer. Now I have no problems in my tank or at least nothing appears to look bad. I have a 29g mixed reef with some SPS that are thriving. My question is what are the chances of my SG being really 1.030? Whatever they are it's always been constant. On the hydrometer I always mixed my salt to 1.025 and I have always measure it from my tank as 1.025. I am thinking I calibrated it wrong some how. Is there any way the refractometer could be damaged or as long as it's calibrated properly it works? Thanks for any help, Zac

01/03/2009, 02:44 AM	#2
AusWog Registered Member Join Date: Apr 2007 Location: Australia Posts: 60	im having the exact same problem, identical my salinty is 1.030 on my refracto and 1.026 on my hydrometer, im thinking the hydrometer is out of wack and old ive been told some only last 6 months some times.is it ok to use tap water to calibrate the refracto or does it have to be distilled water? __________________ Whoops that wasnt a salt water fish? Current Tank Info: 180Gallon Reef

01/05/2009, 02:27 PM	#10
CheckitOut Registered Member Join Date: Jun 2008 Location: Baton Rouge, LA Posts: 426	I also rescently bought a Milwaukee refractometer, and my question is do I adjust to the solution that I bought or do adjust it to distilled water, which method is better? __________________ Geaux Tigers!!!!!!!! Current Tank Info: 105 gallon sps tank

01/05/2009, 03:14 PM	#12
SHOmuchFUN Registered Member Join Date: Dec 2003 Location: Vermont Posts: 4,461	I just got a refracto for my tank and found my salinity to be 1.030 as well. Swing-arm hydrometers are NOT accurate, but I had been using them for years. Near as I can figure, my tank had just become accustomed to the higher specific gravity. An evolution of sorts. I am gradually watering down my water changes and occasionally scoop out a liter or two of water and let the topoff do its thing. I'm not surprised as to your reading and doubt it's because your refracto is not calibrated. They typically come calibrated from the factory. __________________ Erik Engstrom President, Vermont Marine Aquarists. Current Tank Info: Custom 180gal, 6x80w ATI T-5s, (2) Tunze 6025, Vortec MP40w, MSX200 w/ red demon, controlled by AcJR.

01/03/2009, 09:27 AM	#3
Reefer07 Registered Member Join Date: Aug 2007 Location: Connecticut Posts: 2,090	Either way I find it hard to believe everything is doing perfectly well but my SG is at 1.029-1.030. I tested my bucket of salt I use for W/C and it measured the exact same. The only thing I am concerned about is it talked about the temp. and said the prism has to match the sample temp. etc. etc. How does one achieve this? Or maybe no one does this at all.

01/03/2009, 09:37 AM	#4
Eldredge Registered Member Join Date: May 2002 Location: Eagle, Idaho Posts: 306	It is best to calibrate your refractometer with a calibration solution that is the correct salinity (like PINPOINT calibration fluid). It is not unusual for a refractometer to be accurate at 0 (distilled water), but way off at 35 (correct salinity). As far as temperature, the only thing I would think of is to allow time for the tem to equalize. Mine compensates for temp, so I don't know for sure.

01/03/2009, 12:53 PM	#5
qfrisco Registered Member Join Date: Dec 2007 Location: Dallas, TX Area Posts: 1,389	Not sure which model Milwaukee you have, but I have a Milwaukee ATC100. The instructions call for using distilled water to calibrate to 1.000. However, calibrating with the Pinpoint solution (which comes standard at 1.0264) showed that the distilled water calibration was 0.002 off. If this same thing is happening in your situation, your actual SG is really 1.028, still high, but not AS high. Either way, the key to everything is stability. As long as your livestock eased into 1.028, they should be fine. Also goes to show just how resilient these creatures are!

01/03/2009, 11:39 PM	#6
Reefer07 Registered Member Join Date: Aug 2007 Location: Connecticut Posts: 2,090	1.000? I put some distilled water in and turned the screw until it was on the 0 line exactly on the right side. So say it is really 1.028ish....as I slowly bring it down to .025 when it reaches 1.025 am I going to see any better growth/coloration in my corals possibly?

01/03/2009, 11:45 PM	#7
Ebmorri Registered Member Join Date: Jul 2006 Location: Littleton, CO Posts: 662	Heres a read on calibrating Refractometers http://reefkeeping.com/issues/2004-06/rhf/index.php

01/04/2009, 06:43 PM	#9
Reefer07 Registered Member Join Date: Aug 2007 Location: Connecticut Posts: 2,090	Thanks for the help qfrisco and the link ebomarri. Frisco you got it right that my tank is about 26g + a 10g sump with probably 6ish gallons of water in it.