Issues with Milwaukee MA887 Refractometer

[Nhjmc]

Ye

These are on sale all over the place for Black Friday. I saw one for $89. I used to pay that for refractometers, so for me that is a great deal.

I saw that too lol figures. I did get mine to work Though. Unplugged battery for ten seconds and hold hand a lil above and over the test well I read light can affect that and boomed works like a charm. I love it wish I’d gotten sooner.

 

[Nhjmc]

I know this is old, but that is so nonsensical that I just had to correct it. No matter what they claimed, 0 ppm TDS RO/DI water is perfectly fine for calibrating a true seawater refractometer like this one.

It is also a fine idea to check them with a 35 ppt seawater standard, but I recognize that the Milwaukee cannot actually be calibrated using it.

Thank u. I did get it to work by unplugging battery for ten seconds and putting hand above/ a lil bit over the test well (as read that can matter) calibrated using distilled water. Works great now.

 

[Randy Holmes-Farley]

Yes, but 0-1 ppm tds RO/DI is PERFECTLY suitable for this purpose. Don’t be misled by generalized and oversimplified but incorrect info provided by manufacturers.

 

[Randy Holmes-Farley]

Regardless of how nonsensical it sounds(I actually agree with you), but I can tell you it does make a difference. When using RO/DI my milwaukee is always .002 then calibrating with steam distilled.

FWIW if you run out, email or call milwaukee. They will gladly ship you out a new bottle free of charge.

No it cannot make a difference. It is exactly known how much the refractive index of 0-1 ppm tds water deviates in refractive index from totally pure fresh water, and it is very small in relation to the specs for this refractometer.


Distilled water is also not necessarily purer than 0 ppm TDS ro/di:

https://education.ti.com/~/media/029608482684423FAD45D941FEAD5B99

Fresh distilled water, by comparison, will usually have a conductivity of 0.5 to 1.5 mg/L TDS.

 

[kartrsu]

Happy thanksgiving all.

This thread about calibrating the MA887 made me second guess my own protocols, so I went through vigorous calibration and testing with my refracto. Used rodi near 78F to calibrate and then tested homemade solution as Randy specified (right on point to the hundredths of grams) and I get exactly 35ppt. Even tried their steam distilled and I still get 35ppt. Doesn’t seem to have a difference.

Fwiw, per the manual, you can use deionized water (not sure if entirely different from RODI).

 

[ckalupa]

Agree @Randy Holmes-Farley i was posting the pic info more so to illustrate the mfg statement on calibration of the MA887 at 1.000. I know this was an older thread initially.

 

[Brett S]

I suspect that this note is more to prevent people from trying to calibrate with tap water than preventing people from calibrating with RODI water.

 

[Pistondog]

As you found, ambient light will affect reading, sunlight is worst since it has all wavelengths.
I think the water sample wants to be at the same temp as the measuring device. The ATC sensor is buried in the unit, sensing the cold air in your basement. You put a warm sample on to test and it is off. Wait a few minutes for the sample to cool off to ambient for better results.

 

[Randy Holmes-Farley]

I suspect that this note is more to prevent people from trying to calibrate with tap water than preventing people from calibrating with RODI water.

Yes, I agree. Manufacturers often dummy proof their products, sometimes at the expense of reality.

 

[vinnyol]

I having the issue that reads air when I am calibrating or testing salinity. I have removed battery and still reads air. I cover the entire area of either calibration solution or RO water. This unit is 3byrs old.

Just wanted to give an update: The Milwaukee Ma887 was dropped and therefore the air reading. I was told that the slightest bang or bump will damage the unit

 

[amazongb]

I know this is an old thread, but don't want to start a new one.

I just purchased a new M887 (black) unit. I used the included distilled solution to calibrate, it showed 1.00. Then using the included test solution of 1.025, it tested to 1.027 on my unit. Do I need to send this thing back or is there a fix for this?

 

[Scorpius]

I have an old unit back from 2014 that I still use. Accurate every time. I test it against a tropic marin hydrometer.

 

[Blown]

I know this is an old thread, but don't want to start a new one.

I just purchased a new M887 (black) unit. I used the included distilled solution to calibrate, it showed 1.00. Then using the included test solution of 1.025, it tested to 1.027 on my unit. Do I need to send this thing back or is there a fix for this?

I am having the exact same issue with mine. I calibrate the test with the solution and get anywhere from 1,025 to 1.028 using the same solution. I have tried stabilizing the temps and it seems to make no difference.

 

[BostonReefer300]

That's a pretty big swing. Are you sure you don't have any air bubbles? Are you cupping your hand above the sample to block most of the light? Can you confirm temp reading on the unit with a good reference thermometer?

 

[Gtinnel]

I got one about 6 months ago and I also calibrated with the included calibration solution and then when I tested the reference solution mine didn't match either. What I found out was that their reference solution is not always what it says it is. I made my own reference solution with table salt (it's incredibly easy to do if you have scales to measure out salt and water) and it reads exactly what that solution should be.

Basically don't trust or use their reference solution it's garbage.

 

[amazongb]

I got one about 6 months ago and I also calibrated with the included calibration solution and then when I tested the reference solution mine didn't match either. What I found out was that their reference solution is not always what it says it is. I made my own reference solution with table salt (it's incredibly easy to do if you have scales to measure out salt and water) and it reads exactly what that solution should be.

Basically don't trust or use their reference solution it's garbage.

Can you post the recipe for making the reference solution from table salt?

 

[Dkeller_nc]

There are several possibilities about the variation that you're seeing. One is that you've got a defective unit. Possible, but doubtful. The second one is that you have a defective reference salt solution. Also possible, and far more likely than a defective actual unit.

Here are a few procedural notes that should give you consistent readings:

Very small amounts of residual solution (whether salt, calibration solution, or rinse solution) can strongly affect the reading. For that reason, it's important to clean the window (with RODI and a paper towel), place a sample of RODI water on the reader, and zero it.

When ready to take a measurement, either tank water or a calibration reference solution, remove the RODI off of the sample window with a dropper/pipette. Then using a separate, dry pipette, place the solution to be measured on the window, remove it, then place a second sample on the window and read it. If you only have one pipette, you can eject the RODI from it, suck up a bit of the solution to be tested, shake the pipette to ensure that the test solution removes any residual drops of water from inside the pipette, expel the test solution, refill it, and place it on the unit to read it.

A comment about the temperature equilibration. I've personally found it important to get the sample to be tested and the unit itself to be close in temperature (within a degree Celsius or so). If the unit itself is much colder than (or warmer than) the water to be tested, you will get incorrect readings. Ditto for the RODI water that you use to calibrate it. For this reason, I place the unit (and RODI if I'm going to zero the unit) in the cabinet of my tank's sump. Within about 10 minutes, all components are quite close to tank temperature, and the unit will read accurately. A comment about this - don't leave your refractometer inside the cabinet permanently. The unit is not completely waterproof, and salt spray will eventually make its way into the unit and onto the circuits, and trash it.

 

[Gtinnel]

Can you post the recipe for making the reference solution from table salt?

Here is the quote from Randy Holmes-Farley from the thread I uses to make mine.

"For a refractometer:

Use 3.65 weight percent sodium chloride solution to match 35 ppt (sg = 1.0264). It can be made by dissolving 3.65 grams of sodium chloride in 96.35 grams (mL) of purified freshwater."

Again don't forget to use table salt not reef salt, and this only works with refractometers, not hydrometer or conductivity salinity measuring devices. You can also scale the recipe so that small differences in weight won't matter as much. I'll link the thread, and Randy also has a article linked from there that goes into more detail than anyone would ever need about saltwater.

DIY Salinity calibration solutions

Randy, In light of another post on calibrating a conductivity meter, I decided to give it all a shot on my own system. I read through your article on DIY salinity calibration (http://www.reefkeeping.com/issues/2004-06/rhf/) and have a few questions for my simple brain. 1. Is the Brand MORTON...

www.reef2reef.com

 

[Pistondog]

The instrument and water sample must be at the same temp, so wait a few minutes for tank sample to come to instrument temp.
Rinse window with sample water 1st, dry then apply more sample.
Keep out of sunlight when testing.
Zero with rodi

 

[nim6us]

It’s tough because I have been using calibration fluid and even with that depending on the time left in the well the results fluctuate.

Regarding temperature from my understanding that’s only a factor for SG where PPT isn’t affected by temp.

I found a great video from Treasure Corals where they were doing a comparison on testers and he stumbled into the same issue I’m describing.



I’ve since done experiment on my DT water. I pressed read immediately and then read the same sample again every 1 minute for 6 minutes. I did this with 3 different samples to compare the data, so 18 total readings. And the result was the same on all 3 samples.

From reading the sample immediately up to the first 2 minutes the results were fluctuating. BUT after from the 3 minute mark to the 6 minute mark the results were rock solid.

The conclusion for me; I’m going to continue to calibrate once a month and when I take a sample I’ll wait 3 minutes before taking a reading. I’m sure there’s a million holes in my theory mostly because Milwaukee says in their instructions there’s a plus or minus range of TWO whole PPT.