De-nitrate is an economical, natural, porous material with a pore distribution and geometry that promotes both aerobic nitrification within the first few millimeters of depth and anaerobic denitrification at the core. The material has a high surface area and supports a high density of bacteria. Although de-nitrate has capacity to trap nitrate, this, as with other nitrate retaining materials, such as certain zeolites and synthetic resins, is quite limited. It's primary mechanism of nitrate removal is by anaerobic denitrification like live rocks or reef rocks. Efficiency is magnified several folds by forcing the water to filter through the porous de nitrate. As with reef rock, anaerobic conditions are achieved by the porosity and the depletion of oxygen by the aerobic process at the surface. Excessive flow rates should be avoided, as they may impede development of an adequate anaerobic environment to support denitrifying bacteria.