I've been looking for crushed argonite to use as the substrate in the african cichlid tank that I'm starting. I found some on amazon.com, but all of them say that they're for marine aquariums and some say that they contain live argonite and marine bacteria. I might just be being paranoid, but I've never used this stuff before, so I just want to make sure that its safe to use it in a fresh water tank. So is this stuff okay to use? Thanks in advance.