honestly, i have never in my life though my tank would make such a major improvement just from switching salt's! this is the best salt i have ever used in my life. my corals extend from their skeleton farther then ever and the water is so clear that it looks emtpy! it comes with 2 bags of salt (sodium chloride & magnesium) Part A & part B liquid components, 5 very nice measuring cups and a liquid measuring cup. also a nice chart explaining how to mix the salt that is very well written. lets just put it this way, i have always used instant ocean before i switched to ESV. instant ocean is like jersey shore ocean, and ESV salt is like the Great Barrier Reef!