Judy

your original post said your TC was 2.0 and FC was 2.0 and that would mean your CC was 0. My first reaction was going to be "why do you want to shock?"
If the water was clear and CC=0 then there is no reason to shock. Then much later I see the you mention mustard algae. That changes things.

Maybe someone with more experience can help both of us here but I would have thought your CC would have been up some if you have mustard algae. OR does mustard algae not yield measurable amounts of CC? So was the test not good or the mustard doesn't cause CC to rise?