3 6 9 Tesla, if you understood that, then you could hold the keys to the universe.
Stevie, Add a second Mini Tesla, While you are doing that, Also look for the eleventh harmonic.
Be sure the second Mini Tesla is not identical to the first, as your not looking to boost power, but to apply a second frequency to the water. When Coil 1 and Coil 2 is at the tuned frequencies the water will generate the Third harmonic on its own.
However, if one wanted to skip the above, Increase the size of the Tesla coil, Add a second Mini Tesla identical to the first using a seperate Isolated power source.
A tesla coil should be designed so that it could be Tuned, as so for the second. There will be an eleventh harmonic at every frequency. Which of those tuned frequencies does water react to? Well with my Mini tesla when I put my hand on the glas container, I could feel the water Thumping the Container as if it was Pulsating in a way it could Bust the glass. Try feeling its heart beat on the external part of the glas stevie. Put your hands on it and feel it pumping the glass jar.