Many years ago I used Reef Crystals exclusively in my previous tank, and when I setup the new one I went back to it, but I changed over due to the film left behind in the mixing container. From there I tried Fritz (original), Oceanic, Seachem, Tropic Marin, and Aqua Vitro.I now use Kent or Coralife, whichever is priced right at the time of purchase, and usually buy 3 or 4 boxes at a time.