For all NSW users or bros planning to use NSW, would like to bring out that since the oil spill (that has been cleared up) a couple of weeks ago, a few bros have reported fishes dying with unknown reasons after doing WC with NSW.
There is no proof that there is oil residue in NSW that are causing harm to the fishes, however I do not believe in coincidences as well.
Perhaps more bros can chime in here on their experiences, if any. In the meantime, in spite of the lack of evidence against the hypothesis, I suggest to bros here to use salt mix with RO/DI water.