What are you using to get 15,000V, a neon sign transformer? I bought a new TDS pen that measures in single digits and diluted 1000ppm calibration sol'n down to 20ppm and calibrate the pen to that to check my CS and RO water. I just use a 28vDC wall wart for power and a simple current limiting circuit to adjust the current flow to keep particle size small. Supposedly you can multiply the reading by 2 - 2.5 to get a close approximation of the actual ppm but it takes electron spectroscopy or something like that to get true ppm and most of the stuff sold is just a wild guess as to it's actual concentration.
Personally I doubt that 10ml CS to a gallon is going to do much including causing hermies and certainly not cause crazy growth. Why would you want to kill off fungi in your medium anyhow?
I figure my CS to be around 12-15ppm and it works great for tooth infections and things like toenail fungus. My wife uses it on her chickens when they get infections. Adds it to their drinking water and sprays some on any wounds to good effect. We keep a small sprayer in the bathroom so it's handy for small cuts etc.
I've been meaning to take a couple of clones and treat one with CS to see what happens so must do that soon.