The following info was click & pasted from the caribsea web site:
Aragamax Sugar-Sized Sand:TM
0.2-1.2mm diameter grain size (approx.) Also known as "Oolitic sand", this product is ideal for shallower beds, allowing denitrification in as little as 1" depth. The fine grain size can pass easily through the gills of gobys and other sand-sifting organisms. The smooth round grains are gentle to soft bellied sharks and rays. White in color and metal free, no ash or silica. Product #00930 (30lb.)
I prefer to mix this type sand with caribsea sea flor grade sands...
Seaflor special Grade Reef Sand: TM
1-1.7 mm diameter grain size. A revolution in reef keeping! This is the one you've been reading about in all the hobbyist publications. This grade of aragonite is specifically engineered for plenum-type nitrate reducing beds. The pore water space created by precision grading also allows maximum Ph support and dissolution of calcium carbonate.
Product # 00020 (18lb.), #00050 (44lb.)
in my opinion these 2 types combined with Natures ocean LS is a great foundation for a DSB.