Refugium Sump

thats pretty wicked

Neato!

Do mangroves serve a nitrate absorbing function? Is it for aesthetics? Or something else?

Mangroves grow much to slow to really be a viable source of nurtient export so my official answer is NO.

they still absorb nitrates. its not like the dont do it at all.

IMO they help your tank if you have them, why do you think they grow on the coast line?

The answer to the question in summary is yes they absorb nitrates in a limited way but they look very cool.

This is from the Daniel Knop article in the Advenced Aquarist Online Magazine:

"Mangroves take the nutrients necessary for their growth from the aquarium water. This means that we have a means of exporting phosphates and nitrates. Macro algae do the same, but they easily set those nutrients free when they are eaten by fish or die and dissolve. With mangroves this is different, at least if the aquarist succeeds in preventing the mangrove leaves from falling into the water and dissolving there. While many mangrove species export excess salt by depositing it on the surface of their leaves for the rain to wash away, some mangrove species deposit excess salt inside of their oldest leaves, which then will turn yellow and drop down. This is a natural process, but in the reef tank we just have to make sure that the leaves will not dissolve in the aquarium water and release nutrients back into the aquarium water.

But, on the other hand, regarding the nutrient export capacity of some mangrove plants living on the upper zone of our reef tank, we should not expect miracles. They are slow-growing plants, and their nutrient uptake is limited. To say it clearly: if we have the problem of exporting phosphates and/or nitrates from our tank, due to over-feeding, insufficient foam fractionation, etc, we will certainly not be able to solve it by planting mangroves. Having mangroves in the tank just helps to make the man-made biotope a little more natural, in function and appearance. If we try to create something we call a "mini reef," we should take every opportunity to employ natural mechanisms. Even though their functional contribution to the system is relatively small, it makes our "mini reef" a bit more natural."

plus their root systems create a whole habitat!!