Your water is defenetly cleaner than mine...
I have a question, how did you measure the capacitance of the cell?
When I try to use any of my 3 Cap meters, I get no reading at all.
Also 34 Microfarads, that can't be right.
http://www.daycounter.com/Calculators/Plate-Capacitor-Calculator.phtmlOne time I was persuaded to insulate the tubes, my cell was a little bigger, also 3" long but using 1" and 3/4 diam tubes.
and the capacitance of the insulated tubes with water (Real Capacitor) was 8nf.
also when I calculated using the web page above, the results was also close to the 8nf.
so your cell with smaller surface area has to be less than 8nf.
Jolt