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  1. #1
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    Refractometer help!

    Hello Everyone
    It has been a long time since i had a question.
    This one seems easy but i 've done a lot of reading and i am truely lost.
    I bought a Refractometer (RS-RHSN-10ATC)
    My problem seems to come from the temperature variance.
    I do calibrate the unit with RO/DI water.
    but when ever i test the water, results varies and even with new RO water it seems to be out of scale again, and again...

    Now my Reef water is always at the same temperature.
    Should i get the RO/DI water at my Reef's temperature to calibrate it?

    Any sorts of procedure you guys employs or any tips and tricks
    i mean i paid the thing 50$ and from where i stand my ol hydro whois .004 off is more usefull, but i would love to know 100% how to use it and be 100% sure of the results!!
    Please help this noob :b7:
    90G + 40

  2. #2
    Senior Member
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    Jan 2009
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    Ok i did one more test.
    Since its an ATC unit (suposed to be automatic temp control)
    ive set it up with fresh ro water, calibrated it to 1000
    i left it on my desk for a few minutes then it was at 1002
    so even if its an atc the temp does change smthing ?!?
    i am getn deeper in it my friends....
    90G + 40

  3. #3
    Former Moderator a4twenty's Avatar
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    SG is influenced by temperature. if you made two water samples to the same SG, one 10 deg warmer than the other then raised the temp in the lower one, the SG will change and they wont match. most manufacturers recommend calibrating the unit at a set temperature ( usually 20C or ~ room temp. ).


    they usually will recommend you allow the sample to sit on the prism for at least 30sec before reading. this allows the bimetal strip ( what makes it an ATC unit ) time to match the sample temp and properly compensate.


    it's also not a bad idea to use a calibration fluid from time to time for better calibration accuracy, i've done it both ways and found little difference but they say over time this can change.

    HTH
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  4. #4
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    If you go to the website I cited in an earlier answer to one of your refraction questions, you can see which angles you need to measure and how to use them in the equation of Snell's law to determine the index of refraction of the medium you are testing.

  5. #5
    Senior Member
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    Quote Originally Posted by orson.octavius View Post
    If you go to the website I cited in an earlier answer to one of your refraction questions, you can see which angles you need to measure and how to use them in the equation of Snell's law to determine the index of refraction of the medium you are testing.
    Thx Bud (A4)
    i had the answers but i didnt understand them!

    Orson im lost @ your answer...
    If i was lost before, imagine my lil brain wrapping around that!
    I couldnt find the link on any of my old post.
    I'll try n google some more on the physic's law you are refeering!
    90G + 40

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