I use Tropic Marine. It is one of the highest grade salts used in the industry. It mixes well, no cloudiness unlike instant ocean that can cloud your tank if not mixed thoroughly. Another great brand to use is CoralLife Salt. I use to CLS until the store in my area swithced to using all Tropic Marine Salts in the show tanks because of the better grade salt. You'll pay a bit more, but well worth it.For those of you with reef tanks, if you want to use an Instant Ocean product, make sure you use Reef Crystals.