Are all aquarium refractometers like this?

Discussion in 'Equipment' started by gerbilbox, May 16, 2011.

  1. gerbilbox

    gerbilbox Guest

    My refractometer has trouble holding its calibration. It'll shift by a couple ppt if I accidentally bump it against something in my cramp room, or even after putting it down on the table for a moment. Arghh. I've used lab quality refractometers back when I used to work in a lab and I don't remember them being so fickle. Is my refractometer a POS that needs to be replaced or is this pretty typical quality for aquariums?
  2. seminolecpa

    seminolecpa Past President

    I check mine often, but i have rarely needed to calebrate it and it is a simple Marine Depot one that I have had for many years. Sounds like you may have a POS on your hands or your resultes are getting corrupted somehow.
  3. sfboarders

    sfboarders Guest

    I think my MD is one of those POS. I calibrate it every time I use it. I calibrate it one day and the following day I check the calibration and it's off.
  4. Sfork

    Sfork Guest

    I paid $35 for a generic ATC one on ebay. It came calibrated and I've only had to adjust it once in a year.
  5. GDawson

    GDawson Guest

    That's why I use an old fashion glass hydrometer. No calibration.

  6. gerbilbox

    gerbilbox Guest

    Sounds like I have a POS; it's from Marine Depot. If I'm extremely careful I can get consistent results more often than not, but it's been too frustrating one too many times.

    So the next question is, what would you recommend for a non-shitty refractometer? Is the one at Bulk Reef Supply any good?
  7. rygh

    rygh Supporting Member

    I have used the MD refractometer for about 4 years now.
    Only re-calibrated once. And I do check with distilled water every once in a while.

    1) How is it stored? Drafty garage?
    Large thermal cycles can throw off calibration on any instrument.

    2) Do you clean it after use?
    You might build up a thin mineral deposit on the glass, and that
    would throw it off, causing all sorts of calibration issues.
  8. Coral reefer

    Coral reefer President

    Happy with the brs one so far. Only had it a few weeks
  9. sfboarders

    sfboarders Guest

    Do you calibrate with calibration solution or distilled/RO water?
  10. rygh

    rygh Supporting Member

    I calibrated with distilled water.
  11. tuberider

    tuberider Guest

    +1, I calibrate before each use, they all slip a bit and are temperature sensitive no matter what the box says.

    AFA using RO to calibrate it's not the best idea
  12. Vincerama2

    Vincerama2 Evil Overlord

    I've had one for many years that I used to calibrate all the time, but now I don't because I'm lazy. Thanks for the reminder! however, it was never as sensitive as you say yours is!

  13. sfsuphysics

    sfsuphysics Supporting Member

    calibrate? bah!

    I check my tanks water.. see what that is at, then I mix up my fresh salt water to match what the tank is.
  14. tuberider

    tuberider Guest

    And I'm assuming you check your tank water by sticking your finger in it Mike? :D
  15. Coral reefer

    Coral reefer President

    I do mine by taste!
  16. rygh

    rygh Supporting Member

    Another trick is to measure the water at the LFS when you buy coral or something.
    While that is far from guaranteed to be correct, and is not useful for calibration,
    it is valuable if you see a value you do not expect.

    At the very least, you know you need to calibrate and check again.
    And regardless of the number, if it is different from your tank,
    you know you have the be extra careful with acclimation.


    BTW: The reefkeeping article has another point worth repeating:
    Be careful not to get the wrong type of calibration liquid. (conductivity versus refractive)
  17. Mr. Ugly

    Mr. Ugly Past President

    That's why we've made refractometer standards to give away.
  18. GreshamH

    GreshamH Guest

    FUNNY POST EVER!!!!! Oh wait, yours serious? Unless you are using a high end NON hobby hydrometer, you could get more accuracy from tasting it. A single bubble can ROCK your world ;)

    This thread is HILARIOUS. MD vs BRS vs XXX vs xxx If you know the truth, which looking at packing will reveal, you'd understand most all these "brands" are simply rebadged same Chinese product.

    If you want to break from the mold and get a truly useful refractometer, get the D-D one (which was in the BAYMAC raffle). I love mine. I have used pretty much every hobby recfractometers and even high end scientific grade units. The D-D one ROCKS for the price and it puts all those rebadged blue box POS to shame.

    To keep you POS blue box in calibration more often, drip a little hot wax into the threads of the calibration screw. The screw backs itself out due to the poor construction.
  19. Sfork

    Sfork Guest

    I thought my generic chinese crappy one looked exactly like the others offered :D
  20. Gomer

    Gomer Honorary Member

    My MD refract is rock solid...The set screw is has also corroded frozen over the years of use :-D

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