I started back in 87' on IO and switched to Reef Crystals only because the store I dealt with was out, and over the years I've tried quite a few.....I've tried Seachem and didn't like the inconsistencies between the batches and how it mixed as well.....RedSea I wasn't pleased with at all, Oceanic it seemed my tank inhabitants didn't like the change, Tropic Marin Pro, I really liked, but honestly for the money I didn't really notice any real difference in my tank between that and Reef Crystals.....Kent salt I didn't like as well, mixing issues, and Coralife is just poor IMO.....they had (have) issues with the mix. I've also had a friend that mixed his own salt and my tank responded incredibly with his mix ratios, but the mixing was horrible, because of precip, but gave that mix up and went back to Reef Crystals......