difference in water qualities in different locations

[Ice_Phoenix87]

differences in water qualities in different locations for example the great barrier reef and the central coast of NSW. they would probably have different amounts of trace elements, etc? This is in relation to using bought salt from Shops with trace elements etc (using money) or getting water from the local beaches around the central coast (free). this water is much cooler, i believe that any bacteria whether good or bad will probably die from the temperature change and the temperature will probably effect the concentration of trace elements etc in the water. Note: this tank is a great barrier reef style tank.

So what is everyones opinion