# Re Using Ph Buffer Soloution



## sink cut (26/6/10)

Hello,
I have a new PH meter which I calabrated 2 nights ago when it arrived. The amount of 6.86 and 4.00 solotion provided is so litte that I put it back into its litte bottles.

I am mashing today and thought I'd just check the PH meter to make sure its still calabrated. Instead of reading 6.86 in the buffer it read 7.3. 

So the question for me now is do I re calabrate using this used buffer, or do I just trust my original calabration (2 days ago).? 5 points is a big deal in the mash, so I must choose wisely.

Thanks

David


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## sink cut (26/6/10)

Ok, Just went to the hydroponics store. They said to never re use the buffer, so I got some more. My PH meter was about .3 out with the new solution, therfore I re-calibrated.

I have to say, This ph reading stuff seems pretty hit and miss


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## RdeVjun (30/6/10)

Good question and you're right, pH is sometimes a bit iffy. As someone in the water quality industry, I'd recommend getting larger quantities than the piddly amounts of standard that often come with the probe or meter, just work out which particular ones your probe needs to calibrate in the range you're interested in and source from a lab supplies outfit rather than a retailer way down the food chain. 
Standard re- use is fraught with risk, but if you're sensible with how you do it then there's no big drama, just don't pour the stuff for re- use back into the original bottle, use another container (well- cleaned and rinsed obviously). Any contaminants on the probe when you dip it into a standard will impact on the reliability of the re- used stuff but it isn't hard to minimise that. If you get a decent quantity from the right place though, that shouldn't really be necessary in the long run. 
I'd perhaps try here (WQ Instruments (pdf)) if you're in Brisbane where the rep I know is pretty amenable to some home brewing, but there are quite a few other specific lab supplies outfits- google might be your friend.

My 2c, hope this helps! :icon_cheers:


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## sink cut (30/6/10)

yeah, I have larger amounts of fluid now, enough not to worry about re-using. I guess it just makes me concerned that if my meter can go out of calibration so quickly - how accurate is it when I am actually using it?

The best i can do is just to calibrate it before each mash, and if not accurate, at least I hope it will be consistent. My Mash last weekend read pretty well, 5.5 during Protien rest then down to 5.3 during starch conversion. So I must at least be in the ball bark.


Thanks

David


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## davelovesbeer (1/7/10)

Yeah, recalibrating is a good idea, but I wouldnt reuse buffer. Also you have to make sure that the sensor part of the probe is properly imersed to get a good reading, especially for calibration.

Try looking up laboratory suppliers, such as Merck, crown, or Lomb, I buy 500mL bottles for the lab at work for $10-20. This should last a while. Maybe pool shops might sell as well.


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