Using mangroves as a type of [tag-self]filtration[/tag-self] in a salt water system was started by Julian Sprung several years ago. He planted a mangrove into one of his aquariums just to see what would happen and to his surprise it actually started to grow and flourish. An article was produced by Julian Sprung detailing the benefits of utilising mangroves in an aquarium and many aquarists started to utilise mangroves as an additional form of nutrient export.
Mangroves can be grown in various areas of the marine aquarium system. They can be grown in the sump, the refugium, the mud bed, a separate designated aquarium or even in the display aquarium if you so wish.
Mangroves, similar to an algae based system utilise nutrients from the water to aid in their growth, the primary nutrients utilised are phosphate and nitrate therefore as with macro algae they are a good tool for use as a [tag-tec]nutrient export[/tag-tec] device. The difference between mangroves and macro algae is that when macro algae dies in the aquarium all of the nutrients which they have taken up are released back into the water column, mangroves do not directly release nutrients back into the water, but to ensure that this does not happen the aquarist does need to ensure that any old yellowish looking leaves do not fall into the aquarium water.
Some mangroves export salt via their leaves which in nature the rain naturally washes away, however in the aquarium this is not the case so alternative measures need to be taken. There are, however other mangroves which deposit excess salt into their older leaves. These older leaves then fall from the mangroves and in nature get either washed away or slowly rot down, however in the aquarist’s case they go into the aquarium where they will dissolve and release nutrients back into the water.
One thing which must be noted is that mangroves are not as fast growing as macro algae therefore the nutrients they can physically consume are limited to the speed of growth of the actual mangrove. Therefore if you are having problems with either nitrates or phosphates in your aquarium then this will not be able to be solved via mangroves alone, however adding mangroves to an aquarium which is not experiencing nutrient problems is an excellent way of providing an additional way to export nutrients.
In the aquarium where we hope to grow mangroves we need to ensure that it is open at the top and that there is sufficient space for the mangroves to grow. If you are planning on introducing mangroves to a closed top system you may have to cut an opening for the mangrove to grow through.
If you are planning upon adding mangroves to either an additional aquarium or to an existing macro algae, mud bed etc based system then all you need to do is place the mangrove(s) into an area where there is enough space above to grow.
Mangroves normally grow in mud, however there are variants which are able to grow in lime rock. The lime rock needs to be porous so that the mangrove is able to push its roots into the pores of the rock. To plant them into mud you simply gently push the root area of the mangrove into the mud. An alternative way is via the use of a basket whereby the ‘root ball’ is placed into the basket and then the basked is pushed into the mud. The basket needs to have holes on the sides and bottom so that the roots can push through into the mud.
It is recommended to support the top of the [tag-ice]mangrove[/tag-ice]. A good way to do this when your mangroves are in the sump area is to wrap polystyrene around the stem so that the polystyrene floats on the water surface and prevents the mangrove from falling over. At a later time hen the mangrove starts to grow this support can be removed.
If you are thinking about growing mangroves in your display aquarium then do not place them in a location which is directly underneath a metal halide. The reason for this is that there is too much heat directly underneath the bulb and this will burn the plant. Place them where the light they receive is not direct.
If you are thinking about growing mangroves in the sump for example either in a designated aquarium or combined with other algae then fluorescent tube based lighting will be sufficient as long as the tubes in question are designed for the growth of plant life. The best tubes to use are those which have a Kelvin in the region of 6000. These tubes have more yellow and red in them which benefits plant life.
Another good way to light mangroves is by the use of natural daylight. If you can place a designated aquarium where direct sunlight will fall then you can grow mangroves in this way. The best growth I have seen in mangroves is from those which receive natural daylight/sunlight.
The thing about mangrove plants which I like is that they do not require much care and maintenance. The mangrove types which export salt via their leaves for it to be washed away by rain need to be cleaned – this can be achieved by spraying fresh water onto the mangroves therefore washing the salt away. This needs to be performed 2-3 times a week. Do not spray an excessive amount of fresh water or the aquarium salt water could be affected. Or, perhaps better, carefully wipe the plant with a well moistened clean cloth (using fresh water). This is a more tedious task however.
For the types which export salt into the leaves which will fall off then these leaves need to be removed when they start to go yellow. Try not to let any of these leaves fall into the aquarium water as they will quickly dissolve and release nutrients.
The final thing you need to do is occasionally trim the plant back so that it does not grow too close to the lights. Cutting the mangrove back occasionally also helps it to grow more dense than tall.
The final thing I must point out is that once you have put the mangrove into the aquarium do not be tempted to move it. The reason for this is that the mangrove acclimatises itself to the conditions it is placed in and moving it will cause it stress and potentially cause it to die.
It would be great to hear your experiences with mangroves, have they been successful, did they grow etc – post a reply below.