Water change from a local spot at the ocean, or estuary.

It can work out good!

Look in the water in that area or at least test the water!
Personally I always put a mask and snorkel on and look at what lives there, if things look good the water will be good!

If no hair algae yet or other problematic life not in your tank yet, let the water sit for a few weeks in the containers bt do not allow any evaporation, its best that way, then use it! One of the most popular sites that water is collected and sold to the hobby here in SEQ comes from a site that when I dive there, my wetsuit stinks of sewerage and there are stacks of heavy metals and other harbour pollutants there in the water.

Where I get water from, for my tubs at our Brisbane’s bay side, I go to the boat ramps there, the water is brown and looks crap, but around 80 to 100 feet out from there, there are acans, sps and so much more growing there, because dirty water is rarely bad water quality.

Plus if the wind is off shore, as in blowing from the shore out to sea or out into the bay from the shore, there are no pollutants on or near the surface!