PH Pen calibration Solutions

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Hi Guys,

I've bought a pH pen on ebay over in the UK. This unfortunatly did not come with the pH 7 and pH 4 buffer solutions for calibration ?

Would u guys have ANY idea where I could get hold of those solutions in order to calibrate my meter ?

Cheers
 
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Would u guys have ANY idea where I could get hold of those solutions in order to calibrate my meter ?
You can ake your own 'checking' solution very easily (and cheaply...):

Mix 3.8 grams of Borax into 1 liter of RO water. (buy the borax at you local chemist, and ask him to weigh off the amount for you...).

This solution has a very stable pH of 9.18 at 25°C (and only varies from 9.23 to 9.14 between 20°C and 30°C), and it is thus ideal to check if the pH calibration is correct.

HTH
Hennie
 

DeanT

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Just make your own solution and tst it using a test kit
Use vinegar which has a ph of about 2,5 and use a alkaline to neutralize it and this will bring the ph closer to 4 or 5

I calibrated my ph probe over the weekend using ro water and and watered down vinegar

Worked perfectly
 
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Just make your own solution and tst it using a test kit
Use vinegar which has a ph of about 2,5 and use a alkaline to neutralize it and this will bring the ph closer to 4 or 5

I calibrated my ph probe over the weekend using ro water and and watered down vinegar

Worked perfectly
I would not trust this method at all...

Here's a link to making your own http://www.ffcr.or.jp/zaidan/ffcrhome.nsf/7bd44c20b0dc562649256502001b65e9/146fd852cd5e269049256f32001a133e/$FILE/B30.pdf

but really purchasing a std is really so much easier. We spend so much on our systems and livestock - why skimp and possibly mess everything up for the sake of a R100 or so.
 

DeanT

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as long as you are able to verify the PH of a liquid using a test kit , i dont see the problem in using liquids you have access to .

if you test a liquid and the kit indicates the PH is X , then great , you now know the PH verified with the kit , and therfore you can use it to calibtrate the pen.

i understand about skimping on R 100 but why waste this , just to use it once , when we have access to so many different liquids with different PH.
just think about the liquids you have around your house , and you will find that there is more than enough to choose from.

i my case , i bought a PH probe , it had no indication of the PH in the bottle it shipped with .
so one who assume it would be 7 pr 8 .
so i tested it with a test kit , and it ended up being 4.5.

the bottom line , if you can verify a liquids PH , then i dont see why you cant use it
 
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It's just that I don't think using a test kit which you have to interpret colours would be an accurate enough to use as std to calibrate a pH pen.

That's like using a matchbox to measure the length of a ruler.

I don't disagree with the idea verifying the pH of a common liquid and using thsi as a further std, but I dont agree that the pH should be verified with a pH test kit.
 
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I was looking for calibration fluids or accurate buffering solutions and my LFS guy suggested I use mineral water as the ph is on the label and I would presume they would use accurate lab equipment. I checked two bottles of still and sparkling water and saw there is a decent variation between the two due to the co2 addition. This seems like a cheap and easy solution.
 
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I was looking for calibration fluids or accurate buffering solutions and my LFS guy suggested I use mineral water as the ph is on the label and I would presume they would use accurate lab equipment. I checked two bottles of still and sparkling water and saw there is a decent variation between the two due to the co2 addition. This seems like a cheap and easy solution.
Labels are printed in bulk - not for each batch -the pH of the water in the bottle may be quite different from that on the label as the values on labels are only "typical" values.
 
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I am confused whats the difference with the PH 4 and the PH7 ?

I also ordered a ph pen online. I saw the buffer soultion at wild on pets by greenstone
 

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