Mangroves absorb nutrients from the water in order to grow, and help lower nitrates and phosphates in the aquarium.
A. Thiel has conducted a special research. Three aquariums with the volume of about 22 gal (about 80 liters) and three aquariums with mangroves. Each aquarium had aproximately 20lb ( somewhere around 10 kg) "live rocks". In each one of those aquariums sat an ordinary yellow tang. Every one of them had the same protein skimmer.