in short the response i got from seachem was, to be able to match real ocean water they have to add more than average calcium to mimic real ocean water.
i mix it for a day or 2 in a 65 gallon barrel and wipe it clean when im done transferring it to jugs. even though its a pain in the a$$ to mix, i find to to be the best salt Ive used.
also when adding it to the tank keep your power heads running, the water will clear up eventually....