# Proper cleaning of pH-electrode



## sonaps (Nov 15, 2005)

I just got off the phone with Milwaukee Instruments, Inc. My pH probe had stopped working after a cleaning and I had called to get it replaced as it was still under warranty. What I found out though is that I had ruined the probe myself by cleaning it with a toothbrush. In case anyone else out there is as ignorant as I was about how to clean these things I though I would pass on the information they gave me. They said that you could soak the electrode in rubbing alcohol for 1 to 1 ½ minutes and swish it around a little. They recommend doing this after any major change in your system, like a water change. Obviously you would want to rinse the probe and recalibrate it after such a cleaning. I went on their website after talking with them and there it says you should soak the probe for 10 minutes in the rubbing alcohol and then soak it in RO water for 2 hours before recalibrating.

Another helpful item they mentioned is that these probes usually need replacing after a period of 12 to 15 months. A good way to tell if they are in need of replacement is to put them in Windex with ammonia and see how fast the reading goes up to 10, it should be very fast. They said it doesn't matter where it stops just so long as the reading is above ten. You can tell that you may need to replace the probe if the reading goes to ten very slowly or if it doesn't ever get there. They said it's kind of like a light bulb, when the filament burns out its time to change it. Further detail about this is also on their website. They said the reason Windex with ammonia is good for testing is that it has a high reading with no buffer to "pull" the reading up, like is used in the calibration solutions. I guess the father on My Big Fat Greek Wedding was right; Windex can be used for everything.

There is other useful information on their website about why the probe needs to remain wet, why you can't reuse calibration solution etc. Here is the link: http://milwaukeetesters.com/english/technical_tips/ph-ec_info.pdf
Hope this helps others to not make the same mistake I made.


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## summitwynds (Jun 3, 2005)

Thank you for taking the time to post that information. It is something I wondered about.


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## Gomer (Feb 2, 2004)

very good info indeed. thanks. Guess what I'll be doing when I get home.


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## fish7days (Jul 30, 2005)

Thanks, I just went thru this a week or so ago and evidently was lucky as I did use a toothbrush !!!


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## bergzy (Feb 18, 2006)

another method is:

i soak all my pH probes in vinegar for at least ten minutes. low level acetic acid would seem a little less harsh than rubbing alcohol.

old reef aquarium guys tried and true method.


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