# [SOLVED]hydrostatic density meter schematic

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#### cocoon

##### Guest
ph metre diy

Hallo Forum,
I would like to apologize for my a little bad one English first. I would like to build a pH-meter for me. the pH- meter shall serve for the co2 supply for an aquarium. many thank for your help.

#### shorty

##### Member level 2
Hi
here´s a circuit but it´s not siple to build
a PH meter because uf the extremly high
impedance of the probe (>1GOhm)
it´s easyer to by it of coure at https://www.conrad.de or so

good luck Shorty

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#### House_Cat

I agree with the above. Most of the cost in a Ph meter is the probe. An accurate probe is not a trivial thing to make yourself.

"PINPOINT" makes a Ph meter for about $90US that comes complete with a probe and ready to use. A probe, suitable for continuous use, will cost you about$50US if you buy it without the meter.

One company that sells PINPOINT brand Ph meters is:

https://www.aquariuminstruments.com/

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#### Guest

##### Guest
On 2002-03-02 09:06, cocoon wrote:
Hallo Forum,
I would like to apologize for my a little bad one English first. I would like to build a pH-meter for me. the pH- meter shall serve for the co2 supply for an aquarium. many thank for your help.

This is really easy. All you need is a
7106 LCD meter chip, adjust the reference
and offset for the probe. You can go right
into the chip, it is high enough impedance.
See the application notes from Intersil if
you can find the old ones.

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