I use Reef Crystals and feel that there is a difference. Granted, I don't know that there are considerable effects, but while I do a water change I know that there are certain elements that are being taken from the tank. With Reef Crystals I am equalizing the change, which doesn't alter the tanks condition. Anyway, my corals seem to like it and there is no price difference at my LFS... It really just depends on your preference.