Some if not all of us use artificial salt mix, some purely some on and off alternating with NSW. The local brands are not good enough for corals. they will support fish but not inverts. Imported available brands are tropic marin, red sea, reef crystals and others. You can contact PETSNEEDS, MARINE HU
B or PUGO1 all below for salt mix. The important thing is we do not use tap water when mixing salt mix. Usually RO water ( the water in the bottled water suppliers ) is the preferred choice. Some of us have had luck with filtered tap but if you want to be sure that tyour water is free of excess phosphate, nitrate or silicates you should use RO water. I once did a water test of our local manila water QC tap stuff and found it free of nitrate or phosphate but i think its best to be sure. If you're on a budget though, NSW is cheaper - just be sure you are getting it from a reputable source.