pH measurement

[CokFLHX]

I have always just used the test strips that you dip in whatever solution and read the color compared to a chart. It does good enough for extractions, but I was wondering if anyone could suggest a better way to measure pH.

I’ve no experience in any of this. Never been in a lab. So I don’t know what is available or the technology behind pH meters.

That being said I seen on Amazon I can get a pen with an electrode that is meant to be dipped in whatever you’re measuring.

Is this a viable solution? How accurate is it? I assume the electrode are consumable. If so, how often do they need replaced?

If I can get a pen for $25 and it last 100 dips, and reads with digital accuracy, I can’t see a downside.

What’s the consensus amongst the pros?
I plan on doing this enough that I would justify the investment if there is a widely accepted tool that is considered to be better than the dippin’ strips.

Thanks

 

[drpotato]

you can get the pen for $5 dude. What is important is calibrating it often. pH is logarithmic, meaning that every unit away from neutral/7 is exponentially larger in magnitude, what raises ph13 to 14 might be 100x more base than what would go from 12 to 13, so the cheaper ones often struggle to read values very close to neutral since it generates almost no voltage to read. but at 1 or 14, no problem, youll get a nice quick stable result.

ph sensors also drift bad, youll generally want to swirl it around and get a reading very quickly, it might go --, 7, 5,4,4.4, 4.1, 4.0. 3.9. 3.8, 3.8, 3.8, 3.9, 4.0, 4.1, 4.1, 4.1, 4.0 ,4.2 and the art of reading it is that 3.8 was where it was. given time it might eventually go back to 5.
dont buy the calibration salts, get solutions and keep them refrigerated until used. be mindful about cross contamination as well, any time you rinse in tap water, follow with distilled water to remove the tap water. verify it often if its going in ph1 or ph14 solutions, and bear in mind the electrode is a VERY thin and fragile (dont touch) glass bulb, ph14 some teks recommend will etch and destroy it. really ifyour ph is 1 or 14 thotheres no need to even measure it really, use the paper. but if you are doing something like figuring out how much base to only reach ph12, you can do so in a 20% dilution or whatever (dilution has almost no impact on ph) and then measure how much lye or carbonate you added to raise the ph in a test tube, and multiply it by the scale you used, so that you can cover the first 80% very quickly then slowly add the last 20% while you have the probe in there.

For best results, in my experience, if you are trying to get a very accurate reading that you know is basic, especially if its like, 8 or 9, soak the probe in a 1% diluted weak acid, like say, vinegar, but diluted 100x so it doesnt mess with the solution you are measuring. that big swing its going to take that causes it to cross the neutral threshhold should help it land on the right spot nice and quick before the drift sets in that cheap sensors have.

you may need to clean the glass bulb at times, but the glass is extremely fragile, so i guess, deal with that. pretend your polishing a puppies eye or something with a q-tip.

Lastly, the solutions you will want are ph4, ph10, and ph7, though 7 is just for confirming that it is capable of reading 7 accurately. if you know what ph you want to read, getting a different solution closer to that specific ph is advisable, they make them in 2, 8 and 12 as well.

 

[CokFLHX]

Please correct me if I’m mistaken, but from what I understand it’s not nessessaey to obtain a precise pH, right? Basically you want it to be less than or equal to a pH of 4 when acidifying, and greater than or equal to 12 when gasifying, right? Using the pH meter seems like more of a pain in the ass to have to calibrate and mess with it when litmus strips can let you know real fast if you’ve hit the mark or not.

Also, again please correct me if this is inaccurate, but when basifying, you can’t OVER base, right? As long as it is at least a pH of 12, you’re good. The way I understand it, you can’t add too much lye. Just has to be 12 or higher.