Sugar fine sand is purported to be the best sized grain for a DSB and is what I use for DSB’s. A depth greater than 4 inches would be better as the idea is to have a completely anaerobic layer at the bottom of the sand bed. Along with denitrification, the sand will very slowly dissolve under these anaerobic conditions and get shallower with time, providing very minor supplementation of beneficial elements. Therefore, the deeper the bed is when initially setting up a DSB, the better.

Some potential problems with a DSB in the display: The rock work may become unstable over time because of the dissolution of the aragonite. Detritus may build up in areas not receiving enough current. Aquarists have a tendency to put critters in the tank that are detrimental to the DSB as they consume the beneficial sand bed life forms that are slowly stirring the sand bed and turning detritus into inorganic insoluble elements. As well as the inclusion of critters that rapidly disturb the layers of the sand bed, eliminating some of the sand beds denitrification benefits. All of these potential pitfalls can be overcome if the Marine Aquarium System is properly planned and these factors are adjusted for.

Each aquarist setting up a DSB must consider the expectations of the DSB. I believe the only reason a DSB should be placed in the display tank is to support animals that require a well established DSB in order to thrive, such as sand sifting gobies and cucumbers. Most systems with live rock, strong current, and a protein skimmer do not require a DSB for denitrification unless the closed aquarium system has too high of a bio-load e.g. too many fish.