I've always used Instant Ocean too ...
Here's a link that may be helpful.
I personally feel that the brand of saltmix is not as important as many other factors that we have some control over.
Even the best saltmix is "junk" if mixed with poor quality freshwater, and the salinity, pH temperature and other water quality parameters are not monitored and controlled.
<a href="http://www.animalnetwork.com/fish2/aqfm/1999/mar/features/1/default.asp" target="_blank">Saltmixes</a>