I know there are a lot of posts on using natural sea water, but I haven't found an answer to this question yet. What specific tests (other than checking salinity) do I need to do on natural sea water to determine if it is safe for my tank? I live a block from two of the top 5 cleanest bays in the U.S. and would love to do the initial fill of my tank with NSW instead of preparing 15 gallons of water at one time. TIA!