Milwaukee Digital Refractometer

[jharding08]

I am having a problem getting my Milwaukee Digital Refractometer to calibrate once I ran out of the 1.000 SG solution provided with the kit.

I have tried using RODI water and water I steam distilled myself. All show a SG of 1.030 when I calibrate with the 1.026 solution I have.

Steps I do every time:
1. Put distilled water in the meter, enough to cover up the eye.
2. Hit zero on the meter, shows 1.000 on the meter
3. Wipe out the distilled water with cloth I got from my manual refractometer
4. Put 1.026 solution in the meter, enough to cover the eye.
5. Hit Read. It shows 1.030

Is there another step I am missing? Shouldn't it know 1.026 once it is zeroed?

I have just been making my tank water so that I reads the same reading as the 1.026 calibration solution.

Things in the tank look good, just spent a lot of money on the digital refractometer, because I was tired of trying to figure out which line on the manual refractometer to use as the reading. Hope I can get this working again.

[water is wet]

I'm guessing your not using solution provided by Milwaukee to check it against since your not using their calibration fluid? If not that's most likely your problem.

If you don't have any you'll need to email them and they'll send it out free of charge.

[Skim]

Well that OK I zero mine and tried the solution that they supplied with the unit and I get 1.023 and the solution should be 1.025,then I test my tank and the Milwaukee says 1.024 and my Red Sea unit says 1.026. Now tell me which one would you believe.

Skim

[jharding08]

[QUOTE=water is wet;23717823]I'm guessing your not using solution provided by Milwaukee to check it against since your not using their calibration fluid? If not that's most likely your problem.

If you don't have any you'll need to email them and they'll send it out free of charge.[/QUOTE

Can I get this from their website? I dont think MarineDepot or BRS has it

[Dmorty217]

I calibrate mine with RO water and have never used the calibration solution they supply. The meter has a correction factor of +-.002

[jharding08]

Originally Posted by Dmorty217

I calibrate mine with RO water and have never used the calibration solution they supply. The meter has a correction factor of +-.002

What am I doing wrong then? Can I manually adjust the meter to calibrate 1.026 solution correctly?

[Dmorty217]

Originally Posted by jharding08

What am I doing wrong then? Can I manually adjust the meter to calibrate 1.026 solution correctly?

You can't adjust for the correction you just have to know it may be that or might be +-.002. I don't think your doing anything wrong if you will. If the glass on the refractometer isn't clean it will also give you false readings.

[jharding08]

Originally Posted by Dmorty217

You can't adjust for the correction you just have to know it may be that or might be +-.002. I don't think your doing anything wrong if you will. If the glass on the refractometer isn't clean it will also give you false readings.

So if my 1.026 calibration solution reads 1.030 then as long as my water is 1.030 then I am fine, right?

[Dmorty217]

If the solution is off then your salinity in the tank will also be off by whatever it is (in this case.004 it sounds like) what I don't understand is if you use RO water and it reads 1.000 why when you read the calibration solution it's so far off?

[jharding08]

Originally Posted by Dmorty217

If the solution is off then your salinity in the tank will also be off by whatever it is (in this case.004 it sounds like) what I don't understand is if you use RO water and it reads 1.000 why when you read the calibration solution it's so far off?

I wish I knew. I clean the glass eye with the cloth provided with my manual refractometer. Does ambient light in the room matter?

[Dmorty217]

No the light in the room shouldn't matter at all

[water is wet]

Originally Posted by Dmorty217

If the solution is off then your salinity in the tank will also be off by whatever it is (in this case.004 it sounds like) what I don't understand is if you use RO water and it reads 1.000 why when you read the calibration solution it's so far off?

I was doing the same thing for 2yrs without any problems and one day it just started reading high so I bought a second unit and right out of the box it read high so I called and was told it was because it wasn't being tested against the correct solution.

After receiving their solution they both work perfect again.

[jharding08]

Originally Posted by water is wet

I was doing the same thing for 2yrs without any problems and one day it just started reading high so I bought a second unit and right out of the box it read high so I called and was told it was because it wasn't being tested against the correct solution.

After receiving their solution they both work perfect again.

IS Milwaukee the only site to sell it?

[water is wet]

There is no charge. As far as I know they are the only ones to carry it.

http://www.milwaukeeinstruments.com/...ct-information

Sales and Support In The United States Only*

Milwaukee Instruments, Inc.
2950 Business Park Drive
Rocky Mount, NC 27804 - U.S.A.
Tel.: 1.252.443.3630
Fax: 1.252.443.1937
Primary:*sales@milwaukeeinstruments.com
Financial Dept:*accounting@milwaukeeinstruments.com
Technical Dept:*support@milwaukeeinstruments.com*

[Dmorty217]

Thanks for the info. Do you have to call someone to get the solution, I'm not seeing it?

[camaroguy]

I have one of these same refractometers, and it reads .001 high very consistently. For purposes of a water change, you technically don't even need to calibrate it, as long as the new water reads whatever your old water reads.

As far as knowing the actual SG, the thing you need to make absolutely sure of with a "test liquid" is that it has the same refractive properties of 1.026 seawater.

Some liquids are made for calibrating a salinity probe at 53mS. While this is the same resistance as 1.026 seawater, the fluid will not have the same refractive index as 1.026 seawater.

I calibrate to 1.000 with the solution provided (until its gone), barely ever calibrate it to be honest. It doesn't seem to drift much. I then check it with a fluid with a known refractive index of 1.026. It always reads 1.027. I know that if my aquarium tests at 1.027, it is actually around 1.026.

Ambient light can affect the readings. I try to use it away from any strange colored artificial light. If I don't believe the reading, I will shield the sensor from ambient light, and it has changed in the past. Also, you have to realize that it takes a little time, 30 secs to a minute for the temp of the water to be the same as the temp of the sensor, this is important because temp affects the reading as well. It usually goes up if you wait a minute. Also make sure there are no bubbles in the water on the sensor. I also cover the sensor a lot, so the water is covering a portion of the edge of the metal dish surrounding the crystal.

[jharding08]

I emailed Milwaukee Instruments. I will let everyone know what they say about getting more calibration fluid

[laga77]

I ran into trouble calibrating mine. The unit I received had a card, along with the instructions, stating to use only distilled water and not ro/di water. Even though the instructions read ro/di. I first used distilled water from Walgreens and was finding inconsistent results. I then tried ro/di water with a TDS reading of 0 and again, was not getting good results. After making my own distilled water, I can get consistent results using a commercial seawater sample. It is a pain sometimes, but this is what I have to do get get the same result over and over.

[jharding08]

I did make my own steam distiller water on the stove expecting to see my 1.026 calibration solution show 1.026 but it showed 1.030. The calibration solution I am using is from American Marine Pinpoint. It is 53.0 mS standardized fluid

[camaroguy]

That's interesting. I also use American Marine 53mS solution, as it is supposed to also be 1.026 refractive index. I always get 1.027 as mentioned above.

Have you ever left that bottle open? Evaporation could affect the actual SG of the solution.

[water is wet]

Originally Posted by Dmorty217

Thanks for the info. Do you have to call someone to get the solution, I'm not seeing it?

I called first and was instructed to email sales to which they replied asking for a mailing address.

[snorvich]

With a standard error of the mean of +/- 0.002 you should get reproducibility constrained by the accuracy of the instrument. I would, for example, not use this as a measure of the accuracy of hyposalinity.

[Dmorty217]

Originally Posted by water is wet

I called first and was instructed to email sales to which they replied asking for a mailing address.

Great I will follow your lead thank you! Steve I know someone using this refractometer for hypo so we will see how it goes. He felt more comfortable with hypo than CP.

[water is wet]

Have either of you heard back?

[Jay_R]

Originally Posted by jharding08

I am having a problem getting my Milwaukee Digital Refractometer to calibrate once I ran out of the 1.000 SG solution provided with the kit.

I have tried using RODI water and water I steam distilled myself. All show a SG of 1.030 when I calibrate with the 1.026 solution I have.

Steps I do every time:
1. Put distilled water in the meter, enough to cover up the eye.
2. Hit zero on the meter, shows 1.000 on the meter
3. Wipe out the distilled water with cloth I got from my manual refractometer
4. Put 1.026 solution in the meter, enough to cover the eye.
5. Hit Read. It shows 1.030

Is there another step I am missing? Shouldn't it know 1.026 once it is zeroed?

I have just been making my tank water so that I reads the same reading as the 1.026 calibration solution.

Things in the tank look good, just spent a lot of money on the digital refractometer, because I was tired of trying to figure out which line on the manual refractometer to use as the reading. Hope I can get this working again.

I have this refractometer.. And it works a dream.. Maybe I've missed something, but how do you know the 1.026 solution you are adding is indeed 1.026?

All I do is add the mixed water to the reader, hit read and bosh 1.026 provided I measured my salt correctly.