I've used Tropic Marin, Kent, reef Crystals, Instant Ocean and one or two others I can't remember the names of. Personal preference is Instant Ocean (1st synthetic salt used for clownfish breeding). Been using it for 15 years unless it's not available then Reef Crystals or Kent. Reef Crystals will give you a higher Ca+ concentration initially and you may save a little on supplements. Still prefer Instant Ocean, myself.