Milkuakee digital refractometer off by .001

[Miami Reef]

I zeroed out the distilled water and then I added the green seawater 1.025 solution and I got 1.026. I then cleaned the machine really well with RODI and tried again and I keep getting it .001 higher.


Does this mean that I should deduct .001 to get my result? How can I properly calibrate this unit?

 

[Pistondog]

I zeroed out the distilled water and then I added the green seawater 1.025 solution and I got 1.026. I then cleaned the machine really well with RODI and tried again and I keep getting it .001 higher.


Does this mean that I should deduct .001 to get my result? How can I properly calibrate this unit?

Make sure you wait a minute or 2 for the sample to reach instrument temp.

 

[Reefer Drew]

Is the calibration fluid brand new? If not, possible evaporation giving you a higher reading.

 

[Snoopy 67]

What is the instrument tolerance on readings?
I would have no problem accepting that one.

 

[Miami Reef]

Make sure you wait a minute or 2 for the sample to reach instrument temp.

Ohh. I didn’t do this

Is the calibration fluid brand new? If not, possible evaporation giving you a higher reading.

Its brand new

 

[Reefer Drew]

Ohh. I didn’t do this

Its brand new

I agree with Pistondog then, allow the fluid to reach instrument temperature and then read

 

[Miami Reef]

I just tried again. It still reads .001 higher.

Should I exchange for another one? Or should I make a new calibration solution? I can’t tell if the machine is not accurate or if the standard is a little higher.

@Randy Holmes-Farley

 

[vetteguy53081]

Must calibrate especially if new

 

[Miami Reef]

Must calibrate especially if new

There’s no option to calibrate. It’s basically just zeroing the water and double checking if the solution is reading accurately. There’s no way to change the readings.

 

[Pistondog]

Re zero after temperature equilibrium with rodi, if you haven't already.

 

[vetteguy53081]

There’s no option to calibrate. It’s basically just zeroing the water and double checking if the solution is reading accurately. There’s no way to change the readings.

As Pistondog indicated OR Typically you will use drops of solution ( such as 1.024 solution and it should read that value)

 

[Miami Reef]

Looks like accuracy is 0.002.

So if I get a reading on my tank that shows 1.025, do I subtract .001 since calibration showed higher, or not?

I’m going to make a test solution with the manual instructions and see if it’s possibly the solution that’s a bit higher.

 

[Pistondog]

Looks like accuracy is 0.002.

So if I get a reading on my tank that shows 1.025, do I subtract .001 since calibration showed higher, or not?

I’m going to make a test solution with the manual instructions and see if it’s possibly the solution that’s a bit higher.

I like a 2nd source verification, like a manual refractometer.
Or take a sample to your lfs.
But no harm in trying your manual test solution.

 

[MnFish1]

Your result is within the error of the instrument - dont subtract or do anything - just use the instrument - in addition to the temperature caveat.

 

[MnFish1]

PS - I would say - thats not the best refractometer perhaps? I mean if the difference is +- .002, that means that lets say the SG is 1.025 - it could actually be 1.023 to 1.027. A manual refractometer - calibrated to seawater - seems much more accurate. This instrument - is not sensitive enough (IMHO) - to do what you're trying to do

 

[MnFish1]

As Pistondog indicated OR Typically you will use drops of solution ( such as 1.024 solution and it should read that value)

But - even if you use a 1.024 solution - the reading - according to the manual could be 1.022 or 1.026 - and still be within the margin of error of the device.

 

[vetteguy53081]

But - even if you use a 1.024 solution - the reading - according to the manual could be 1.022 or 1.026 - and still be within the margin of error of the device.

1.024 is an example although I see what you are saying. I want a number- not range why I parted with mine and went with other digital

 

[Miami Reef]

Dang it. Everyone was talking about how good this unit is.

I need something with a digital readout and ACCURATE.

I think the best solution is the tropic marin Hydrometer? Anyone else have something they really like?

Tropic Marin is extremely accurate, but one issue is that it needs temp to be controlled. I don’t think that will be a problem for me.

 

[vetteguy53081]

Dang it. Everyone was talking about how good this unit is.

I need something with a digital readout and ACCURATE.

I think the best solution is the tropic marin Hydrometer? Anyone else have something they really like?

Tropic Marin is extremely accurate, but one issue is that it needs temp to be controlled. I don’t think that will be a problem for me.

This is supposed to be one of the best

 

[Miami Reef]

This is supposed to be one of the best

Are you talking about the tropic marin