# can we measure pH using multimeter?



## keithy (Jun 8, 2010)

I have a fundamental question about measuring pH and I hope someone can help me understand this. 

My question: can we measure pH using multimeter?

reason for asking: water acts as resistance for conductivity at different ph levels(H and OH content in water). thus, if we can measure resistance using multimeter, can we link the resistance to pH by a handheld multimeter?


thank you in advance for your clarification.


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## Misfit (Sep 3, 2010)

I can't answer this myself, but I am interested in what others may say.


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## lipadj46 (Apr 6, 2011)

short answer is no you cannot


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## BS87 (Apr 9, 2012)

lipadj46 said:


> short answer is no you cannot, in a way that is any easier or cheaper than conventional methods


Modified that a bit


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## dmagerl (Feb 2, 2010)

what you are describing is a TDS meter.


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## samamorgan (Dec 31, 2011)

Not with _just_ a multimeter, no.


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## keithy (Jun 8, 2010)

can anybody explain why this cannot be done?


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## PlantedRich (Jul 21, 2010)

Will a guess do for the time being??? I should think the difference in current flow will be very small. With that in mind, I think there will need to be a much more precise way to measure things. Amp up the difference or find a meter measuring much more precise that the normal meter?? Like I say, just a guess but another thought is that if it were that easy, lots of people would be doing it. 

Sometimes the simple answer is the correct one. If it were possible, people would not pay for a seperate PH meter.


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## lipadj46 (Apr 6, 2011)

keithy said:


> can anybody explain why this cannot be done?


pH probes use a glass cell that has a reference solution on the inside. The H+ in the water and the ions in the probe create a tiny potential difference. The pH meter then amplifies this signal so the correlation can be made between voltage and pH. If you hook up a pH probe to a multimeter it does not have an impedance high enough to amplify the voltage. Measuring resistance with the regular multimeter probes won't tell you much about the specific [H+]


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## Diana (Jan 14, 2010)

Another guess:
In an aquarium there are too many other charged particles that contribute to the readings when you test using a multi-meter. 
MAYBE RO water? ? ?


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