Kessil

Are all aquarium refractometers like this?

gerbilbox

gerbilbox

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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?
 
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.
 
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.
 
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?
 
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.

Ideas:
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.
 
rygh said:
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.

Ideas:
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.
Click to expand...

Do you calibrate with calibration solution or distilled/RO water?
 
sfboarders said:
rygh said:
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.

Ideas:
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.
Click to expand...

Do you calibrate with calibration solution or distilled/RO water?
Click to expand...


I calibrated with distilled water.
 
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!

V
 
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)
 
GDawson said:
That's why I use an old fashion glass hydrometer. No calibration.

-Gregory
Click to expand...

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 ;)

gerbilbox said:
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?
Click to expand...


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.
 
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