I just saw now, your interesting threads in here, Don. Thank you very much for them.
To clarify about the + and - voltages. In the present view of physics, there's absolutely no difference if you plug +1000V at one electrode and -1000V at the other, or if you plug +2000V at one electrode and "earth" at the other. Why? Because there doesn't exist an absolute potential level. Only differences in potential are seen (electric fields). An example. If you just go up in the air by 3 feet the potential will usually increase by about 200 Volts! So you see, there's no absolute potential. Even the "earth" potential is different in different locations.
But and here now comes the difference. The water itself also has a potential relative to the environment. E.g. if you take a glass of water and stick a HV DC wire in it, it will for a short while make some sparks until the water has charged to a certain level. One usually says, it has become electrostatically charged. Strictly speaking it's a one terminal capacitor to the environment. If you now stick your finger in the water you will get a small spark, like when you walked on the carpet and then touch a doorknob (the same principle).
So if applying +1000V and -1000V does make a difference in the cell, compared to +2000V and "earth", then only because the water itself had a certain potential relative to them before.
So in this view, it could actually make a difference if you apply +1000/-1000V.
In this relation it is IMHO important to know, that a tubular WFC, like Stan used, does behave differently in relation to charges than 2 plates. Why? Because of the "faraday-cup" effect (inside a conductor the E-Field is zero). This means, if the water has any charge in relation to it's environment, it will give this charge to the outer cylinder and become neutral. This could be the reason, why the outer tube has to be isolated in Delrin. Otherwise it would again give it's charge back to the water around it...
Maybe this could be important. Maybe not...
Ah BTW:
If the upper fact is important, then it would be quite important, that you go again in the inside of the inner tube, before the water (gas) goes out of the tube, and have a delrin cap on top. If you do it like that, the outflow always becomes neutralized before leaving the WFC.
The same for the input plug for the water to the WFC...