AD7746 for Deionized Water level sensing

Question

Hello, 
 I'm trying to detect the DI water level in my small tank (160*30*17mm) and I found this note quite helpful. However, I still have some questions: 
 
 Can I use this scheme to detect DI water level? or does it just work with salty water? 
 Can I detect water level below C2 ~ REF level? 
 Since my tank is relatively small:
 
 How do I calculate the track width and distance? 
 How long should the C2 ~ REF track be?

The PCB i'm using has a 1mm thickness, copper is 1oz. 
 Thank you very much in advance. 
 Best Regards,

JoanOrtega · Accepted Answer

Hi Tekmachi, 
 You can measure any liquid with a permittivity much higher than air. 
 C2 is used to have a constant reference that can be used to calculate the level by a linear relationship between the capacitance of this reference (C2) and the capacitance generated by the length of the sensor under the water (C1), therefore C2 must always be completely under the water. 
 
 The application notes explains how to calculate the plates dimensions for a defined capacitance. You will need to now the permittivity of your liquid and what is your desired capacitance;

Regards 
 Joan)

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AD7746 for Deionized Water level sensing