" While I concentrated on the protozoa, all microbes were destroyed by the end of the test."
That was on a single frequency of 2490 hertz. It was the positive offset that worked. Interesting also beside Hulda Clark . you will see Dr Richard Loyd Phd and Jeff Sutherland use positive offset with frequencies.
You also said another very important factor. TIME. If one invests enough TIME in the Correct type of zapping one will see results (as measured and qualified by real blood tests).