I have been using Tropic marine pro reef since I set up my tank early this year. And I love how quick and clean it mixes. With all the money I have invested in my tank, paying a little extra for a quality product is totally worth it for me.To be honest the biggest reason is the residue that instant ocean leaves in mixing containers it is kind of miserable. Red Sea has always mixed clear and left none. But don't get me wrong some amazing tanks use instant ocean so it is really on what you want to pay for!