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-   -   My new Milwaukee pH56 - calibration issues? (http://www.homebrewtalk.com/f128/my-new-milwaukee-ph56-calibration-issues-348588/)

periwinkle1239 08-19-2012 02:55 PM

My new Milwaukee pH56 - calibration issues?
 
So I bought myself a Milwaukee pH 56 and am really excited to try improving my quality by understanding/controlling the mash pH.

I believe I followed the instructions that came with the meter to calibrate it (I can post them if needed) but afterward I let it sit in the 4.01 calibration solution and the meter reads 3.91. Is that right? It sounds like I'm off by 0.10. Likewise when I move it to the 7.01 solution it was reading 6.89.

Before I calibrated it, it was reading exactly 4.00 in the solution so I'm wondering if I should've even bothered trying to calibrate.

I also read the sticky on here which is a bit more detailed and has a few more steps such as rinsing the electrode with DI water, so I may try that next time I calibrate.

ajdelange 08-19-2012 03:44 PM

Go back to the sticky and read up on the stability check part. It is characteristic of inexpensive meters that they aren't stable. It is also characteristic of users new to pH measurement that they don't always get things exactly right the first time out. So do follow the more detailed instructions of that sticky with respect to DI rinses, blotting, fresh buffers etc. If it is up to you to decide when to accept a calibration reading wait a good minute or 2 before accepting and at the completion of the cal, read one of the buffers several times over a period of an hour or so. Some fluctuation is to be expected. We hope that as you, and the meter, get broken in a little you'll get that down to less than 0.1.

periwinkle1239 08-19-2012 04:02 PM

Thanks! When I did my research I think I bought a reputable and somewhat pricey meter, so I think I just need to figure out how to use it correctly to get accurate readings.

RCCOLA 08-19-2012 07:01 PM

I suggest you soak the probe for 24 hrs in storage solution to condition it before using it. Hanna recommends 1 hr, but it wasn't enough for my meter.

My cheap Hanna read .5 off after a 1hr soak. I adjusted it and then placed it in storage solution. After the overnight soak, it read .5 off the other way. I reset it with fresh 7 and 4 buffers. Since then, it hasn't deviated more than .1.


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