ATI Fiji White Sand is a fine white substrate with grain size between 0.3 to 1.2mm (comparable to Caribsea’s sugar-sized aragonite sand). What makes Fiji White Sand different than other popular marine aquarium substrates is it is marketed as a calcium and magnesium substrate (99.6% pure) that is heavier than comparable aragonite sand (with the stated benefit of being less likely to be blown about by water flow compared to similarly sized aragonite sand). Fiji White Sand also appears to be more white and reflective than popular aragonite substrates.
These characteristics lead us to believe this sand may be dolomite or possibly calcite – similar calcium carbonates to aragonite but with some notable differences. Dolomite contains a lot more magnesium and is denser than aragonite. Dolomite (and calcite) also has less ability to buffer high pH, which would make it less ideal for reef tanks with low pH (e.g. tanks running calcium/CO2 reactors). On the other hand, dolomite substrate may work great in tanks with higher pH (e.g. tanks running Balling/2-part method and/or Kalkwasser).
Fiji White Sand is now available in Europe for about 18.00 € per bag; No word if ATI plans to export their new sand to the United States or Asia.