onewarmguy
Well-Known Member
Does anybody know how long the calibration powder that came with my Ph pen is good for? If I was to store the mixed fluid in a small sealed mason jar, would it spoil?
PH Pen: Calibration fluid shelf life?
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That stuff usually has a best by/expiration date on it (like about everything else anymore), over time I'm sure it loses it's accuracy, same as if it gets contaminated by your pen as it is a one use kind of thing once used. Not sure on the powder once mixed as I have only used the liquid kind at home and where I used to work.
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onewarmguy
Well-Known Member
Hey Dwight, thanks for the answer, but I'm wondering how much a "best before" is worth when it comes to water balanced to a specific Ph. The Ph has been adjusted to say 6.8 using the chemical contained in the package dissolved into distilled water, if it's kept in an airtight container in the dark, where are the chemicals that provide that specific Ph going to go? Stable humidity and temperature means it can't evaporate, and the darkness won't provide any energy for a photo reaction that might change the composition.
Call me curious, but I'm gonna try it and see, I've got a Ph drops kit so I can get a decent idea of Ph and then check it by pen and see how close it is.
Call me curious, but I'm gonna try it and see, I've got a Ph drops kit so I can get a decent idea of Ph and then check it by pen and see how close it is.
Not sure if things can grow (organisms) in distilled water (I have never experimented with that), but things like that might affect it's shelf life once mixed (that and the liquid ones do have a date on them for whatever that worth, so the manufacturers feel it has a shelf life).
Bush Doctor 77
Well-Known Member
Chemical changes can occur, and if it is ever exposed to air, there is always biologic contamination.
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onewarmguy
Well-Known Member
Okay all, I've got some mixed Ph4 and Ph6.86 calibration liquid in clean sealed mason jars. I'm going to leave them in closed cupboard for a month and then check the Ph. If there's any surprises I'll let you all know.
Bush Doctor 77
Well-Known Member
I doubt they will change. Your meter may drift, though.
It's not going to spoil, that word has a specific definition that doesn't apply here.
However, as has been mentioned, it's possible (and likely) that pH calibration solutions can become unusable due to coming in contact with things in the air. While, again, they won't spoil, if/when the pH of one's pH meter calibration solution changes, lol, it's no longer usable for its intended purpose.
I don't remember off the top of my head whether this is likely with all three, I do know that it's a concern with the 4.01.
The powder stuff is good if one doesn't go through a lot, because you always have the option of making smaller amounts of it. Just remember to maintain the same ratio, obviously.
However, as has been mentioned, it's possible (and likely) that pH calibration solutions can become unusable due to coming in contact with things in the air. While, again, they won't spoil, if/when the pH of one's pH meter calibration solution changes, lol, it's no longer usable for its intended purpose.
I don't remember off the top of my head whether this is likely with all three, I do know that it's a concern with the 4.01.
The powder stuff is good if one doesn't go through a lot, because you always have the option of making smaller amounts of it. Just remember to maintain the same ratio, obviously.
