Hydro/Aquaponics Idea - Will it Work?

[JK47]

OK, so I have a bunch of mangroves trees thriving in freshwater for quite a while now. I took down the 135 gallon tank they where in. I love these plants and want to incorporate them into my new system. They cannot go directly into my tank so I want to try something I have never done before.

I plan on plumbing a DIY plantbox directly from/to my sump, next to my tank. I am hoping to be able to have this system reduce my nitrates in between my water changes. This system won't affect my maintenance/WC schedule though, I like doing WC's. I also just like the idea of using nature to keep things "cleaner" and I am in love with these plants so I want to try and grow them as large as possible. Best of both worlds.

Here is my build idea (sorry for the crappy diagram). You can't see my comments well but you can open the other attachment and zoom in if you like.
View attachment Hydrobox 01.bmp

The idea simplified is to have a small powerhead in my sump running water to inside of a plant bucket full of sand. The water escapes through the bottom of the bucket to the larger bucket that the plant bucket is placed in, then returned to my sump. Since the water being pumped to this box should have zero ammo or nitrite (pumped after bio) I should be able to develope the correct bacertia for consuming nitrates?

What do you guys think? Worth building?

 

[apisto]

you are trying to do two things here that will have the same result, however one of them won't work. You are trying to break down nitrates anaerobically in the lower part of your filter. This won't work since they require a source of carbon such as alcohol to break down nitrates.

However, your mangroves will absorb nitrates and that's the part that will work

 

[JK47]

you are trying to do two things here that will have the same result, however one of them won't work. You are trying to break down nitrates anaerobically in the lower part of your filter. This won't work since they require a source of carbon such as alcohol to break down nitrates.

However, your mangroves will absorb nitrates and that's the part that will work

OK so if I need a source of carbon like alcohol, what else can I do? I would like to have both functions serving a purpose if possible. Is there anything I can put under the sand as a carbon source that I will not have to remove or replace?

Is the carbon source something that can be dosed daily or over time or does it have to be constant?

 

[apisto]

The carbon needs to be constantly dosed. Have a look on the net for 'vodka filter' and you get the idea

 

[JK47]

The carbon needs to be constantly dosed. Have a look on the net for 'vodka filter' and you get the idea

Almost everything on the net about dosing with vodka etc... is for saltwater. This is a freshwater setup.

I still think I am going to build it anyway. I love the look of mangroves and have lots of extra sand laying around.

 

[the_deeb]

I think the hydroponic mangroves are a great but I would ditch the deep sand bed. I would just put them in Hydroton or some other such substrate. I worry that sand with constant downward water motion will eventually compact enough to block your path of flow. Also, my understanding is that you want a very very slow flow rate to efficiently grow anaerobes in a DSB. I think the mangroves by themselves will more effectively remove nitrates at a higher flow rate.

 

[apisto]

Nitrate Vodka Filters work in freshwater as well. For this to work you will need an extremely slow flow rate.
All your deep sand bed will do the opposite of what you are trying to achieve. You will see Nitrate reduced anaerobically to nitrite and hydrogen sulfide. Nitrite being a lot more poisonous to fish and hydrogen sulfide smelling like rotten eggs