The next step will be to work on the electronics. Sadly, my high voltage module suddenly died. I think I know why (I will explain this later). I have ordered another one to experiment with. Hopefully I can get this module to work reliably for a long time. If not , I will most likely resort to using a flyback transformer taken from a CRT.
I have some bacteria testing strips for water that I can use for proof of concept. I will have to resort to more precise analysis down the road.