Calibration Issues: Milwaukee Refractometer

[garrettm]

Anyone else experience this before when calibrating a Milwaukee Refractometer?

I went to test my salinity tonight with the Milwaukee Refractometer and my initial test came out with a S.G. of 1.004. Something was wrong. Tested another sample 1.004 again. Ok, time to calibrate.

I go to calibrate with RO/DI water and get the "LO" error message. I look up the manual and it says this message means the "Wrong calibration used to
deionized or distilled water." hmm... is my RO/DI water bad, doubt it.

Now I pull out the standard calibration liquid "Steam Distilled Water for Calibration Use Only" 1.000 S.G. reading for calibration is still "LO"

https://images-na.ssl-images-amazon....1CYQsDiz7L.pdf

I will call Milwaukee during the week but of course this happens right when I need to verify salinity of a qt tank.

[bertoni]

Have you checked the TDS of the RO/DI? It seems hard to believe that the filtration could be so bad that it causes this problem, but maybe something got into the sample?

[garrettm]

Yikes! TDS is 15 for the RO/DI sitting in the drum. Right out of the unit it says 0 but in the drum it's 15. Something else to address.

I'll see if I can get a truly 0 TDS sample to test.

Thanks!

[GimpyFin]

I started having an issue with my Milwaukee after almost 4 years. I started noticing freshly mixed SW was reading unusually low (Same volume/type/amount of salt and water as usual.) I went to re-calibrate both with my 0 TDS ro/di and with distilled and I got all kinds of readings. I'd calibrate, then do an immediate test with the same ro/di or distilled and it would read about 3-4 points higher or I'd get the "LO" reading instead of 1.000. I fussed with it about 20+ different times and finally just ended up ordering a new one and it's been fine (Both distilled and ro/di as well as the reference solution read accurately now.) I even used the 1.025 reference solution that came with the new one on the old unit and it gave me sporadic readings. Might not be the case with yours, but just a possibility.

[garrettm]

I was hoping that wasn't the case but it may be. The unit is 3.5 years old? Maybe I dropped it one too many times or some liquid has leaked into the internals. Any case I'll probably buy a new one after talking with Milwaukee if I can get a hold of them. I do love this tester.

[GimpyFin]

Yeah, I really like it as well. The original one I bought was the version without the nice protective case and I figured banged it or did something to mess it up.

[garrettm]

Well, milwaukee said to try cleaning the well by letting some windex sit in it for a few minutes and thoroughly wiping it out. Didn't work... There is a 2 year warranty on these guys and I'm unfortunately 6 months out.

Just bought a new one.. Hope this thread helps someone with a similar issue.

[Ron Reefman]

You don't have a $5 hydrometer as a back up? Get one.

Once you get a good calibration on your expensive Milwaukee refractometer, do a comparison of your tank water with both meters. The $5 hydrometer is unlikely to agree with the refractometer, but note the error rate. Mine reads 0.005 to low. Whatever the error rate is, make a label and stick it on the hydrometer. That error rate will stay the same for years. I almost never use my refractometer any more. And it's been over 7 years since I first compared my 2 meters and I do the comparison every year (I used to do it every 3 months for a couple of years) and the error rate never changes.