# Cleaning ph probe?



## mrakhnyansky (Nov 25, 2007)

*Cleaning ph electrode probe?*

Any suggestions what should be done to extend live of the ph probe? I've been reading about cleaning and storing solutions, but no one disclose their chemical composition. I know for sure that bleach can not be used to clean probe for algae. I think when the probe is properly cleaned and calibrated it can serve many years. In the past I've clean the probe with vinegar, Windex window cleaner, and Excel; the best results I had with vinegar acid solution 70% in alcohol. Regular white vinegar is 5% acid solution in water,this is very weak solution. Probe was 2 years old, but after cleaning started to work like new. Any opinions, please post it here.


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## Izzy (Jun 4, 2006)

My bottle of Electrode Care by Red sea fish pHarm ltd. is hydrochloric acid.


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## goldier (Feb 13, 2010)

After testing I wipe off the excess solution with a paper towel, then I dip and swirl the probes in a small cup of distilled water, then take it out, shake it a few times, and let it air dry. They should be ready for next time. Vinegar can be used to clean the deposit on old probes.


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## JeffyFunk (Apr 6, 2006)

I work as the laboratory manager for a small environmental laboratory. We use Mettler Toledo's InLab pH electrodes because they are quality electrodes that really last (unlike, say, anything by Thermo Scientific - the Walmart of scientific lab equipment). The recommended storage solution is Friscolyte B, which is an electrolytic solution of KCl (i.e. potash) in glycerine. They do not recommend storing electrodes in DI water. We've also used pH 7.0 buffer for storing pH electrodes. When they get dirty, we clean our probes with dilute HCl (~1N). If that doesn't work, we've also used stronger acid solutions like H2SO4 (10%). Don't use concentrated acids as they can dissolve the metal parts of the pH electrode.


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## Emily6 (Feb 14, 2006)

I work for a gov't environmental organization and we routinely use YSI multiprobes which include a pH bulb on them. Depending on the range you're looking to monitor, storing the probe in buffer solution is acceptable. pH 4 and 7 I believe is what we store our's in. Soaking them in buffer solution also acts to restore their accuracy. 

DI water is not recommended. You also don't want them to dry out. When not in use (but scheduled to be used soon), we store them closed with a damp sponge (tap water moistened). Keep in mind, ours get beat up pretty bad and have several other probes attached. 

One is also not supposed to scrape at the bulb with, say, a Q-tip or sponge. This can scratch it according to the manufacturer.

Hope that helps- pH probes are notoriously sensitive and tricky.


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## mrakhnyansky (Nov 25, 2007)

Thank you so much Emily6 for such detail explanations on what should be avoided while cleaning the probe( ph electrode). I use Pinpoint American Marine probe to determine ph levels in the planted tank. My ph usually fluctuates from 6.20 to 7.20. I usually calibrate the probe every 6 months. If it's possible, can you please explain what can be done to extend the life of the electrode. Either soaking in storage solution or keeping it for a while in ph 4 solution. American Marine recommends the probe to be changed every 12 months. They also recommend to store probe in storage solution or ph 4 solution ( not ph 7 or ph 10 solutions). Is it really necessary to change the probe every year or there is a way to revitalize it? My next questions about reference solutions. Thank you.


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## JeffyFunk (Apr 6, 2006)

mrakhnyansky said:


> They also recommend to store probe in storage solution or ph 4 solution ( not ph 7 or ph 10 solutions). Is it really necessary to change the probe every year or there is a way to revitalize it? My next questions about reference solutions. Thank you.


Acidic solutions (like the pH 4 solution) will help w/ the removal of mineral salts (which is why they will help to revitalize the probe). There is no reason to change out a pH electrode on a routine basis, assuming that you are able to verify it's accuracy. Please note that it is stated in the EPA method that pH calibration solutions should only be used once and then discarded. (And in case you're wondering, If you use pH calibration standards more than once, I've noticed that used pH standards have a tendency to skew results higher if they are used again, resulting in inaccurate results). (Our Mettler-Toledo pH meter is able to determine the condition of the pH electrode based off of the calibration curve; We change our pH electrodes whenever the condition of the pH probe drops from 3 bars to 1 bar or about every 1-2 months of heavy use.)


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## Emily6 (Feb 14, 2006)

I agree with JeffyFunk- I've never heard of annual pH probe swaps and frankly, if it's holding a calibration for a reasonable amount of time (for portable varieties, I'd say per use- for long-term monitoring, I'd say for two weeks) then it's not worth the money buying a new one. 

Every 6 months is probably a little long to go without re-calibrating. My Milwaukee probe falls out of acceptable range every 2 months. This doesn't mean it's broken- as I mentioned earlier, they will always need re-calibration. We calibrate our YSI multiprobes every day- and they need it. 

Extending the life of a pH probe has more to do with prevention than pro-activeness. Avoid banging it on things, letting it dry out, or scratching it. Calibrate it according to the manufacturer's instructions and yes, always use new solution. Try rinsing it with new solution a few times before actually submerging it in solution to calibrate- this ensures strict contact with solution (my Milwaukee has side walls that trap water).

Hope that helps!


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