here are the list of the ones i have used next to them with their faults i have found:
-red sea: what i first started with, it was cheap, so i got it, however, it was before i had a reef so i didnt test for a lot, but i have heard of a lot of complaints about coral growth and Ca.
-IO: low Ca and high ALK. trace element levels arent always good
-oceanic: not bad, but the Ca was just way to high for me. i used it before i had sps and my crocea, so i didnt have too much Ca usage in my tank, and i was getting readings in the 600s with this. and there were pieces of plastic in the jug.... had nothing to do with the quality, but jsut wierd..... Many people mix this with normal IO which is on the other extream, very low in Ca and other trace elements
-coralife: my corals told me taht they didnt like it too much
-tropic marin: by far the best i have used. my corals seem to love it and all levels are right on, i have not used the pro, but apparetnly that just has more Ca and trace elements.
-IO reef crystals, not bad. but i got a bad batch once that has phosphates in it. it took me a while and for it to kill all but a BB size of my green slimer for me to figure it out. my DI water was free of it, my DI water in the bucket was free of it, but low and behold, once i added salt, it has phosphates..... so id never use that again.
But IMO, as long as you are not using normal IO or possibly red sea, you shouldnt need to dose anything. the reef salts, IMO, have enough trace elements