ime-any of the popular major brands should perform well, or at least, adequately :wink:
i've used IO, Tropic Marin, Reef Crystals, and
Red Sea, and so have my past customers-some have even mixed various brands-with absolutely no discernable ill effects
for my own tanks,-i used red sea exclusively,-and in spite of certain contentions that the ions resulting from the process of evaporating sea salt being improper, as is the manufacturing process involved in red sea-i had excellent results-both in spawning damsels, and w/inverterbrate, and coral health in my tanks. :wink:
fwiw:
i really don't think that the way a salt dissolves, (whether it dissolve completely or not) is an indication of it's quality, w/regards it's ability to meet the various animal's demands
i really thing that the main factor of concern to the hobbyist is the make up of the source water being used to make the sw for the tank, and the price of the salt mix