March 4th IC/CR Meet: LED`s!

Reeferforlyfe · Mar 4, 2012

Posted By blackx-runner on 03/03/2012 03:18 PM

Posted By Money Mike on 03/03/2012 08:21 AM

Why not calibrate with pure ro/di?
Click to expand...

Not as accurate.
Its always best to calibrate equipment with solutions that are close to the point you will be measuring.
Click to expand...

How can rodi not me as accurate, when it's water in its purest form.
Not only that, how can you say mixing a solution yourself can be more accurate? Too many variables when mixing you're own. I let the rodi do the work.

mfisher · Mar 4, 2012

Did you read the link i posted.? She weighed it with an expensive lab scale so its way precise.

blackx-runner · Mar 4, 2012

Posted By Money Mike on 03/04/2012 02:40 PM

Posted By blackx-runner on 03/03/2012 03:18 PM

Posted By Money Mike on 03/03/2012 08:21 AM

Why not calibrate with pure ro/di?
Not as accurate.
Its always best to calibrate equipment with solutions that are close to the point you will be measuring.
Click to expand...

How can rodi not me as accurate, when it's water in its purest form.
Not only that, how can you say mixing a solution yourself can be more accurate? Too many variables when mixing you're own. I let the rodi do the work.
Click to expand...

How do you know its in its purest form? Did you check it? How do you know the scales on the instrument read true. They may be slightly off so when setting the calibration at 0ppt with RO/DI water it could produce an error when checking saltwater at 35ppt. There are just too many variables.
Is it ok to check it with RO/DI water? Absolutely. Tons of people do it, and the error will probably never be enough to cause any issues unless your refractometer is trashed.
But yes for more accurate readings you would want to calibrate it with a 35ppt standard. As the article Matt posted states.
2. The second step in calibration should be performed at
least once before relying on a refractometer to accurately
measure the salinity of a reef aquarium. This step involves
testing it in a solution matching the refractive index of
35 ppt seawater (or some similar solution near the range of
measurement). Remember to let it sit for at least 30 seconds
so it comes to the same temperature as the refractometer.
Suitable commercial and do-it-yourself standards were described
earlier in this article. Using one of them, place a drop onto
the refractometer and read the value. If it reads approximately
35 ppt, or a specific gravity of 1.0264, or a refractive index
of 1.33940, then the refractometer is properly calibrated
and is set to go.....
If you are using a refractometer for hyposalinity, such as
when treating a sick fish, I'd just use one calibrated in
freshwater, because that is closer in salinity than seawater
to the hyposaline solution usually used (say, specific gravity
= 1.009). A new standard for hyposalinity can also be made
by mixing one part 35 ppt seawater and two parts freshwater,
but that is probably overkill.
Click to expand...

Reeferforlyfe · Mar 4, 2012

Ehy, I'll stick with my ro/di.

Reeferforlyfe · Mar 4, 2012

Ehy, I'll stick with my ro/di.

blackx-runner · Mar 4, 2012

Posted By Money Mike on 03/04/2012 08:13 PM

Ehy, I'll stick with my ro/di.
Click to expand...

Works just fine for a lot of people. I would calibrate with RO/DI if my refractometer wouldn't have come with a 35ppt calibration solution.

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