I started in the hobby three years ago. IORC was the craze and everyone said to use it. So, being new to the hobby, I started with that salt. In my opinion, I think people use it because it's popular and it's cheap. I switched to Kent Marine and was not impressed. The levels were low unless I mixed at 1.026 and then I was using a LOT of the salt mix so I wasn't getting anywhere near the amount as advertised. Plus it was very inconsistent. I tried Seachem Reef Salt (I like most of Seachem's products) but found some of the less desirable levels to be elevated. I was talking to a good friend of mine (who also works at the local LFS) and he told me about Red Sea Coral Pro. I bought a bucket and, after three water changes, I noticed a considerable difference. I used it for a year and then, in a raffle, I won a bucket of Salinity. I went through the bucket and I must say I was VERY disappointed. The cost and the results were MILES apart. I switched back to RSCP and I will never switch again! And my corals thank me every time I have to frag them due to amazing color, growth, and beauty!