The use of mangroves plants for filtration in a saltwater aquarium, particularly for helping to reduce and control nitrates is not a new concept. It has been around for quite some time, but few aquarists have really known much about it. However, this is changing because more and more aquarists are looking for a "natural" method of filtration for their aquariums, so mangroves are drawing more attention all the time.
Mud filtration is not required to grow mangroves. They can be grown in a sump, refugium or directly in an aquarium. They are fed by absorbing nutrients and organics from the water, which in turn creates a natural filter for cleaning water. Mangroves not only have the ability to absorb nitrates, but phosphates and other organics as well. In fact, they remove organics so well from the water that they act as a replacement for a protein skimmer. When using mangroves you will notice your protein skimmer working less and less all the time. The more the mangroves grow and mature, the more they absorb the excess organics in your water, and the skimmer has nothing to remove and becomes obsolete.
If you are a naturalist and don't want to have to use chemical additives or compounds to reduce and control nitrates in your aquarium, this is a very effective filtration method to consider.