PH Meter Calibration

[MrN]

Why are you measuring water pH? Its pretty much irrelevant. My understanding is you want to keep the meter constantly moving in the solution. Could it be the water is warming up and that's causing the drift? All measurements should be at 20 degC.

I just wanted to try it out and water pH is one of the fields on some of the water calculators (even though I realise it makes little difference).

[orlando]

I bought a storage solution, ph of it is about 3-4 not sure it's deionised water tbh?

Two questions were asked. Replies respectively.

[orlando]

Is this normal behavior?

Depends on the meter but generally yes. Most meters can take up to 5 minutes or so to settle.

[FUBAR]

Is this normal behavior?

Depends on the meter but generally yes. Most meters can take up to 5 minutes or so to settle.

Yes, my voltcraft meter takes a while to settle but it will eventually.I have noticed that the best way is to after a brief stir of the probe in the test sample, leave it standing by itself securely and it will settle pretty quickly, the slightest movement makes it bounce around on the reading .

[ciderhead]

What are you all using to rinse the probe between the buffer solution tests, as I assume you're using 2 or 3 strengths?

And where do you buy your probe storage solution?

Thanks

Deionised water. Ebay.

So just to clarify you use storage solution, deionised water and calibration solution?
I've only ever rinsed in fresh storage solution.

[Jocky]

I rinse in deionised water in a wash bottle.

[Jocky]

I tend to check mine every 6 months or so.

I do mine every brew. It might seem excessive (every two weeks, on average), but it's usually a little out when I test it. That might say more about my meter though

Mines the opposite every time I've tested it it's still spot on.

What meter do you use?

[Jocky]

As always it is going to depend. When I was doing some lab work at uni, we actually had to calibrate the meter between every reading. Personally I calibrate my meter each time I brew, buying the calibration solutions in 500ml bottles is a lot cheaper that tiny bottles, and they are available quite cheaply from eBay

Do you buy the Hanna solutions or something else? There's a lot of calibration liquids on there for 'hydroponics' but I'm not sure I'd trust their accuracy.

[orlando]

What are you all using to rinse the probe between the buffer solution tests, as I assume you're using 2 or 3 strengths?

And where do you buy your probe storage solution?

Thanks

Deionised water. Ebay.

So just to clarify you use storage solution, deionised water and calibration solution?
I've only ever rinsed in fresh storage solution.

Yes. Rinsing in deionised removes any wort or beer a little more cheaply than storage solution. I just use that for er, storing. I use 7 and 4 pH solution for calibration each time I brew.

[ciderhead]

Cheers

[Dennis King]

Mines the opposite every time I've tested it it's still spot on.

What meter do you use?[/quote]

This is my one. I think I paid £40-50 3 or 4 years ago. When I first got I would test around once a month but as there was never any change I got lax and as I said around 6 months now. After reading this thread I tested agin this morning and still correct.

[Ren]

I bought 2 different brand calibration solutions (hydroponics and some other brand)on Amazon and the difference of ph4 solution when calibrated was 0.3.

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[MrN]

That's interesting. Is there any particular brand of buffering solution people would recommend?

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[Jocky]

There's an old comparison of various brands in the US here: http://reefkeeping.com/issues/2005-02/rhf/index.php

It suggests that Hanna and Thermo Scientific Orion are both consistent - and you would expect so given the expense compared to the chinese/hydroponics ones on ebay.

I've got a couple of different cheap self mix pH buffers, and some more expensive ready made Hanna solution on the way. When those arrive I'll put up a comparison of measurements between them.

[MrN]

Thanks, that's useful to know. Where did you order yours from?

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