Milwaukee Refractometers are not good

BRS

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I ordered this refractometer from Amazon based on the raving reviews on this forum. Lots of people mentioned how easy and accurate it was. Plus you only calibrate it with RODI/distilled water. Provides a digital readout.


I’ve had it since October, 21st, 2021, and I have used it religiously…until I got my first Apex with the salinity probe.

I made @Randy Holmes-Farley Conductivity calibration solution and calibrated the Apex perfectly. It didn’t make sense how my Apex read 34ppt , but the refractometer would say 35ppt.

Plus, the Milwaukee would say 35ppt but when I switched the the s/g mode with the same sample of water, it would show 1.027 which makes no sense.

Tonight I made Randy’s calibration solution for my refractometer (refractometers and conductivity testers use different calibration solutions). I had a refractometer which I used before October 2021 which I calibrated with Randy’s solution at the time, but I made a new batch of calibration using my accurate scale and the refractometer showed 35ppt on the dot.

The same calibration solution (for refractometers) was placed in the Milwaukee unit and it read 37ppt.

In addition, Milwaukee states an accuracy of +/- 2 PSU/PPT. So that reading was “acceptable”.

Finally, I placed my tank’s water in my calibrated manual refractometer and it showed 34ppt, which exactly matched the conductivity apex probe, while the Milwaukee stated my tank was 35-36ppt.

I do not recommend the Milwaukee salinity tester for people who wish to maintain tanks with sensitive corals. Maybe this unit would be best suited for those who maintain FO (Fish Only) tanks, or maybe even soft coral tanks.

Randy’s article for the DIY salinity calibration recipes for any tool used to measure salinity in reef aquariums: http://reefkeeping.com/issues/2004-06/rhf/index.php

Happy Reefing. :)
 
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rtparty

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Close to 4 years on mine and seems to be working just fine

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Randy Holmes-Farley

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Plus, the Milwaukee would say 35ppt but when I switched the the s/g mode with the same sample of water, it would show 1.027 which makes no sense.

That part could easily be explained by rounding.

35.3 ppt has a sg of 1.0266. That would give the readings you see.
 
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The owner of LFS I get stuff from doesn’t like then either. He said you could have three of them lined up next to each other and they will all read differently. I think as long as you are using the same device and it is close to accurate and consistent that’s more important. Salinity checkers have actually been my least favorite part of this hobby. They were driving me INSANE for weeks. I bought a new refractometer, and the tropic marine hydrometer to double check if I was getting weird readings and just try to keep my tank from fluctuating too much. I don’t have any expensive felicitate corals though ;)
 

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The 35 ppt fluid on mine reads off when it is calibrated. I'm not too worried about it though. Most refractometers will read slightly differently from the next. These are all hobby grade tools, As long as it is somewhat consistent, stable, and in the 1.024-1.03 range, I'm happy. I rarely even check salinity anymore anyway. Once you kind of figure out your salt mix formula it doesnt tend to drift. I'll usually just use mine once every time I get a new batch of salt to test the salt mix and then I'll check the tank just to be safe.
 
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thatmanMIKEson

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I ordered this refractometer from Amazon based on the raving reviews on this forum. Lots of people mentioned how easy and accurate it was. Plus you only calibrate it with RODI/distilled water. Provides a digital readout.


I’ve had it since October, 21st, 2021, and I have used it religiously…until I got my first Apex with the salinity probe.

I made @Randy Holmes-Farley Conductivity calibration solution and calibrated the Apex perfectly. It didn’t make sense how my Apex read 34ppt , but the refractometer would say 35ppt.

Plus, the Milwaukee would say 35ppt but when I switched the the s/g mode with the same sample of water, it would show 1.027 which makes no sense.

Tonight I made Randy’s calibration solution for my refractometer (refractometers and conductivity testers use different calibration solutions). I had a refractometer which I used before October 2021 which I calibrated with Randy’s solution at the time, but I made a new batch of calibration using my accurate scale and the refractometer showed 35ppt on the dot.

The same calibration solution (for refractometers) was placed in the Milwaukee unit and it read 37ppt.

In addition, Milwaukee states an accuracy of +/- 2 PSU/PPT. So that reading was “acceptable”.

Finally, I placed my tank’s water in my calibrated manual refractometer and it showed 34ppt, which exactly matched the conductivity apex probe, while the Milwaukee stated my tank was 35-36ppt.

I do not recommend the Milwaukee salinity tester for people who wish to maintain tanks with sensitive corals. Maybe this unit would be best suited for those who maintain FO (Fish Only) tanks, or maybe even soft coral tanks.

Randy’s article for the DIY salinity calibration recipes for any tool used to measure salinity in reef aquariums: http://reefkeeping.com/issues/2004-06/rhf/index.php

Happy Reefing. :)
Same thing I came up with, minus the apex and all the chemistry, but yeah now mine collects dust. +/- 2 acceptable lol o_O
 
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To the people who don’t understand my opinion, would you feel comfortable recommending this tool (which is pretty expensive for a refractometer) solely for convenience?

It’s obviously not accurate. Is it accurate enough for a reef tank? Does it even need to be accurate? Probably not, but I’d say salinity is one of the most important parameter you can test for. If your salinity is off, everything is off.

And if you are using 2 part which raises salinity, you need to be able to track the trends to lower back the salinity. It’s not a tool for a reef tank IMO. +/- 2PPT is not good. For me, accuracy over convenience any day.
 

youcallmenny1

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To the people who don’t understand my opinion, would you feel comfortable recommending this tool (which is pretty expensive for a refractometer) solely for convenience?

It’s obviously not accurate. Is it accurate enough for a reef tank? Does it even need to be accurate? Probably not, but I’d say salinity is one of the most important parameter you can test for. If your salinity is off, everything is off.

And if you are using 2 part which raises salinity, you need to be able to track the trends to lower back the salinity. It’s not a tool for a reef tank IMO. +/- 2PPT is not good. For me, accuracy over convenience any day.
I don't agree that it's not accurate. It slightly rounds but if you clean the lens each time, make sure the temperature of the water you're measuring isn't varying too greatly and calibrate the tool at least every couple of months it should be dead accurate. Either you have a defective unit or you're not using it correctly. It's not a matter of convenience at all but one of accuracy. Mine in no way deviates like what you're saying. I verify the readings roughly bi-monthly with a swing-arm refractometer as well.
 
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I don't agree that it's not accurate. It slightly rounds but if you clean the lens each time, make sure the temperature of the water you're measuring isn't varying too greatly and calibrate the tool at least every couple of months it should be dead accurate. Either you have a defective unit or you're not using it correctly. It's not a matter of convenience at all but one of accuracy. Mine in no way deviates like what you're saying. I verify the readings roughly bi-monthly with a swing-arm refractometer as well.


i clean my lens before and after every use. i make sure all the water is soaked up on a clean tissue. I have the black one from BRS. Mine matches the reference fluid. Did you shake the reference fluid really well?
 

rtparty

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To the people who don’t understand my opinion, would you feel comfortable recommending this tool (which is pretty expensive for a refractometer) solely for convenience?

It’s obviously not accurate. Is it accurate enough for a reef tank? Does it even need to be accurate? Probably not, but I’d say salinity is one of the most important parameter you can test for. If your salinity is off, everything is off.

And if you are using 2 part which raises salinity, you need to be able to track the trends to lower back the salinity. It’s not a tool for a reef tank IMO. +/- 2PPT is not good. For me, accuracy over convenience any day.

It's plenty accurate for our use. Get it around 1.025 and you're set. It makes no difference if your tank runs at 1.023 or 1.027. Just keep it close and you're fine. Salinity is probably the easiest parameter to get right and keep stable.

I run 2 part and have for years.

This isn't an insult or attack on anyone but people make this hobby so much harder than it needs to be
 
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thatmanMIKEson

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I don't agree that it's not accurate. It slightly rounds but if you clean the lens each time, make sure the temperature of the water you're measuring isn't varying too greatly and calibrate the tool at least every couple of months it should be dead accurate. Either you have a defective unit or you're not using it correctly. It's not a matter of convenience at all but one of accuracy. Mine in no way deviates like what you're saying. I verify the readings roughly bi-monthly with a swing-arm refractometer as well.
You lost me at swing arm...
 
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