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Digital ph meter questions

PostPosted: Sun Jun 18, 2017 12:18 pm
by bluc
Couple newbie questions about digital ph meter buffer solution.

To keep it acurate does it need special containers. Can i just use an empty water bottle. Any other special storage conditions needed?

If using an empty water bottle do i need to treat it before use or just dry it then use it?

Re: Digital ph meter questions

PostPosted: Sun Jun 18, 2017 12:22 pm
by Lowie
The ph buffer comes in a small plastic container, you can buy it from jaycar. I use the same solution each time (don't know if that's right or not) but its not something I do very often - these gauges don't go out of calibration too often - actually mine has never changed and I've had it for years.
If you're asking about maintaining your ph tester, a rinse out in fresh water is good enough.

Re: Digital ph meter questions

PostPosted: Sun Jun 18, 2017 12:26 pm
by bluc
The buffer i got is powder you mix with distilled water. Was wondering. Should i buy new bottles or just use couple empty water bottles not sure if previous contents will affect the buffer. Also how to store the buffer solution.

Re: Digital ph meter questions

PostPosted: Sun Jun 18, 2017 1:21 pm
by andybear
I use two empty Vegemite jars ( been through the dishwasher) for the buffer solutions and always rinse the probe and shake gently before dunking it in. To store the probe for long life you should keep it damp with ph4 buffer. I keep a cotton wool wet with the 4 ph in the lid of the probe.

Re: Digital ph meter questions

PostPosted: Sun Jun 18, 2017 1:52 pm
by EziTasting
When I moonlighted as a Labtechnician at a mine site we kept the probes in deionised water (from a RO machine) but I don't think in our case that is warranted. Used to gently dab it on a fresh clean piece of paper towel before using it and rinsing it between moving from solution to solution. As for storage, rinse it clean, I'd dab it dry rather than shaking it (not because shaking will damage it or throw out the callibration, but because it might dislodge the batteries :laughing-rolling: )... then, when dry, store it somewhere where it won't get bumped around or can fall... pretty simple really.

Once this unit poops itself, I might try the litmus papers suggested on another thread on pH testing...

Re: Digital ph meter questions

PostPosted: Sun Jun 18, 2017 1:57 pm
by Triangle
Better off buying a liquid buffer for accuracy. Clean probe in buffer, throw out then test/adjust in clean buffer. Never reuse buffer. Store the buffer at room temp and throw out after 12 months.

Just saw the post above, spot on with demineralised water for storage and clean the probe with demin water. And yep, retest after a knock!

However different meter specs will ask for different storage conditions.

Re: Digital ph meter questions

PostPosted: Mon Jun 19, 2017 4:21 am
by Undertaker
Keep the sampling area wet. Drying the membrane is bad for it.
I use my pool shop for checking my meter calibration. Their wizzbang computerised tester should be pretty accurate

cheers Phil

Re: Digital ph meter questions

PostPosted: Mon Jun 19, 2017 8:22 am
by ant b
We store our probes in a jar of 3 mol/l KCl solution, keep the tip wet

Rinse with deionised water pat dry with paper between buffers and sample to prevent contamination

Buffers can be stored in any container if you follow the steps above will last about 1 year

Re: Digital ph meter questions

PostPosted: Mon Jun 19, 2017 8:35 am
by rumsponge
There are different designs to pH meters.
If it has a traditional glass (membrane) electrode, then it needs to be stored in 3 M KCl or similar. Some of the newer micro- 'electrodes' can be stored dry.
Have you checked your manual ?

Re: Digital ph meter questions

PostPosted: Mon Jun 19, 2017 9:24 am
by bluc
Manual not much help the question was more about using and storing the buffer solution than the ph meter. But the other info is helpful to :handgestures-thumbupleft:

Re: Digital ph meter questions

PostPosted: Mon Jun 19, 2017 10:33 am
by rumsponge
As long as it the vessel is clean, it should be good. These solutions are 'buffered' - meaning they can 'absorb' some acid and base from potential impurities without affecting the pH much,
If you are unsure about the pH of your pH standards, double check with another instrument from a mate (if available) or take them to a pool shop, or buy pH strips (as a backup).

Re: Digital ph meter questions

PostPosted: Mon Jun 19, 2017 10:48 am
by bluc
Cool thanks :handgestures-thumbupleft:

Re: Digital ph meter questions

PostPosted: Mon Jun 19, 2017 12:16 pm
by Whiskyaugogo
Don't forget your buffer solutions will lose their attributes after around 6 months :handgestures-thumbupleft:

Re: Digital ph meter questions

PostPosted: Tue Jun 20, 2017 6:10 am
by scythe
Wow litmus paper is sounding better and better.

Re: Digital ph meter questions

PostPosted: Tue Jun 20, 2017 7:05 am
by db1979
Unless you need to adjust pH to a specific value or range (eg 5.20 to 5.40) then the paper option is all you need. I'm guessing you mean universal indicator paper and not litmus paper. Litmus paper will be pretty pointless. There's products that say they are litmus paper but are actually universal, probably because many people only think of litmus when they think of indicators. Just avoid ones that are blue or red as they are only litmus and will only tell you if you have acid or base, but not how acidic or basic.

Re: Digital ph meter questions

PostPosted: Tue Jun 20, 2017 8:59 pm
by shortybronx88
Log time Chem teacher.... the buffer solution should last a while. Any old container will do.

The instruments work by measuring conductivity of the solution. More acidic, More conductivity to an extent.

Keep it clean and make sure its rinsed in clean water prior and you should be all good. Deionised is best, but any water should do.