this ones for you PEPPIE, sing along now....blue moon, blue moon, blue moon.....BLACK moon tahitian moon sand!!!!!!!!
MY opionion on the "need" for aragontite or otherwise calcium carbonate based substrate in a reef tank is basically nil when you consider the high ph we run in them in the first place how much of that sand is actualy breaking down fast enough to help buffer our water? what about bare bottom? imo substrate is for looks first and critters second so why not use what you like or the critters need.