How to handle mangrove in my 55-gallon FOWLR ?

[chshwong]

Hi there

I'm trying to use mangrove to reduce the nitrate in my 55-gallon FOWLR.
I finally found a source and got 6 today.

It's hanging up there without gravel with open top. It's a bit close to my actinic blue light, and should not be affected by my other 20 W bulb on the other side at the front.
There's no root yet, and here's a picture of how it looks like:
http://img3.imageshack.us/img3/6140/mangrovef.jpg

Here a picture of my whole tank, not sure if it matters:
http://img831.imageshack.us/img831/7469/img4674w.jpg

Now my question is really, do I need gravel while there are no roots?
Or is there anything wrong or things that i can do better with these mangrove?

Thanks!

[Original Fin]

I was interested in doing this a while back for the same reasons, but after researching I decided to go another route. I do remember reading that it is not necessary to provide a substrate while they are growing out roots. As they mature, you'll want to add a substrate, but you could probably wait quite a long time before needing to do this. You will know it if your lights are too low/close because the leaves will turn brown and dry. You may find that your tank lights are way too close right now...typically, mangroves would be placed low in a remote sump, a foot or more of distance between the leaftops and lighting.

I ended up going with a sump/refugium where I will soon begin harvesting macroalgae for the purpose of nitrate and other excess nutrient export. From what I've read, macro algae works better and much faster than mangroves. It can be many months before you begin to see nitrate levels decline when starting out with mangroves. Using macro algae instead comes with another benefit...A typical tank lighting schedule causes PH modulation over a 24 hr period. This is a big deal in a reef, maybe not so much in a FOWLR. When you have a seperate refugium, you can run the grow lights opposite the display light schedule, can reduce/eliminate the PH swing. It is not recommended to do this with mangroves...they are supposed to be on the same lighting schedule as the display...something to do with CO2 availability. BTW, Chaetomorpha is the macro of choice because it will not go asexual and end up in your display tank.

You mentioned that the reason you got the mangroves was to reduce nitrates...Probably the simplest and cheapest way to control nitrates is to do a remote deep sand bed, like 10"-12" deep. This tried and true (if done right) technique was championed by World renown saltwater aquarium hobbyist and author Anthony Calfo. Basically, (and I'm oversimplifying) its a big bucket filled with sand where you run the tank water across the top of the sand bed, where excess nutrients become trapped in the deep sand layers. Lighting is not needed, and it requires very minimal flow. You want to do this seperate from your display, because over time (a couple years depending on bio-load) the sand will become oversaturated and begin to leech nitrates back into the water collumn. A bucket is great, because you simply remove the old one, and add a new one when needed. Depending on the size of your display, the cost to implement a RDSB may be less than $20. I would have done this myself If I had the space under my tank. I'm still looking for a way to make space for it, actually.

[leebca]

A 'mangrove collection' is neat. However it isn't a means to efficiently reduce nitrates. They're ability to do this kicks in when they are mature. Even then, not very good at that. Most I've seen are put through Styrofoam -- roots on the bottom -- foam held in place. No substrate really needed for these.