I need to measure redox value in a pond and got a redox probe to do so. But even using a mV meter, the measured value is running wild and makes no sense. Googled for some hours but got no idea about the impedance of the probe or other particularities to be taken into account. I expected a kind of mV voltage source with an internal resistance of some tens of kOhm which should not be effected by an instrument in the MOhm range. Apparently wrong.
Specifications say: Reference system: Ag/AgCl Metal-electrode: Platinum round end, 6mm diammeter Probe stem: Plastics, 12mm diammeter x 120mm Diaphragma: Ceramics Electrolyte: KCl, 3 mol/l Temperature range: 0...80C
Of course I know dozens of shops and firms that sell complete instruments (I googled around remember) but that's not the point. I want to do it myself. I want to know how and prefer to know why. No need to say I welcome every bit of info you can provide.
petrus bitbyter