# Fluidized Bed/CO2 reactor combo



## exmt (Apr 11, 2006)

Hello, this is my first post on the Planted Tank. 

I want to create a fluidized bed filter(external) and CO2 reactor(internal) that both run off of one powerhead. 

This is for my heavily planted 30 gallon tank with light fish stocking, 2.25 wpg and CO2 injection. This tank is in my formal dining room, so everthing must be aesthetically pleasant(no tubes and wires hanging out all over the place).

This is my current plans of what I will make. Everything is made of sheet acrylic. The fluidized bed filter is square, and there is a flange at the top sealed with a neoprene sheet. The unit is powered with a Maxi Jet 600 powerhead, and plumbed with clear vinyl tubing. Note the reactor is inside the tank, and FBF is hanging on the back. 

So here is my drawing: What do you think? Any suggestions? Thanks!


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## Wasserpest (Jun 12, 2003)

Welcome to The Planted Tank! Nice drawing! Fluidized Sand is more used in marine applications, what do you hope to accomplish? Most of us ADD Nitrates to keep plants happy. Most use canister filters for easier maintenance and superior mechanical filtration capacity.


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## exmt (Apr 11, 2006)

Thanks alot, Wasserpest. I currently have a wimpy HOB filter...so I wanted to upgrade that.

I am hoping to create as small of a filter as possible, but yet still have good biological filtration. A FBF as small as this(size of AquaC Urchin) would be more than enough. 

As I stated earlier, aesthetics are of prime concern. This is why I cannot use a canister filter. I would have nowhere to put it except nex to the tank, as I have a welded metal stand. 

I have heard that trickle filters produce excess nitrates..would an excessively powerful(biologicall) filter like a FBF produce these nitrates? That way, I would have to add less nitrate than I am now. 

Oh yeah, by the way, I enjoyed your article on auto-dosing. I currently am using it on my tank with great results.


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## BlueRam (Sep 21, 2004)

Welcome to the forum! FBF are best for consuming nitrates in things like marine/cichlid tanks. With planted tanks the plants are the filter that can often out-compete the "biological" portion of a filter. Therefore the focus is on mechanical filtration to remove the floaty bits more or less. 

Again, trickle filters and nitrates is much more of a reefer thing. Remember that planted run nutrient rich so the trickle becomes a sump (fuller, less mixing to reduce CO2 outgassing...)

You might look into mattenfilters (think huge sponge filter) or if you like playing with plastic, make a big black (or other color) sponge filter that blends in.



exmt said:


> I am hoping to create as small of a filter as possible, but yet still have good biological filtration. A FBF as small as this(size of AquaC Urchin) would be more than enough.
> 
> As I stated earlier, aesthetics are of prime concern. This is why I cannot use a canister filter. I would have nowhere to put it except nex to the tank, as I have a welded metal stand.
> 
> ...


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## exmt (Apr 11, 2006)

Thanks for the warm welcome, BlueRam.

I understand more pieces of the picture now. Since I have light stocking and lots of plants, I could make a mechanical filtration module before the FBF that is stuffed with filter floss to catch debris before it enters the FBF. Then I could clean the thing out occasionally by opening the flange.

Here is an updated drawing with the new mechanical filtration module, biological module, and CO2 reactor.


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## BlueRam (Sep 21, 2004)

I would still skip the FBF because:
Biological filtration is not as critical and can be overdone.
You will at some point send sand into the tank.
The marble will muck with your water chemistry.
I can not think of another member that runs one (and we are gadget people).

Now keep in mind that I do run a sump which strictly speaking on the basis of water movement is not planted compatible.

If you have compressed CO2 consider an external reactor (rex reactor) and using "lily pipes" for the return so that little to no equipment is visible. There is a DIY plastic thread around. You can also put a heater inline.

Have you considered mounting to the bottom of your metal stand tucked out of the way?


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## exmt (Apr 11, 2006)

How about reducing the amount of sand to limit the total available area for bacterial growth? This way it won't be overdone(at least not too much).

I will replace the crushed marble with some inert aquarium gravel of sorts.

How about posting a new thread asking who uses a FBF?

I use DIY CO2 with 2 generators, each 750 mL. 

Now the Rex reactor is a good idea, but I am trying to reduce the amount of equipment outside of the tank to prevent leaking occurances.

Mounting to the metal stand is a possibility, but I created a little wooden stand on the back to hold my equipment. There is some extra space, so the FBF and Mech modules will be sitting on that.

Anything I missed? 
Thanks,
exmt


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## BlueRam (Sep 21, 2004)

Please do as you like as it is your tank.

Rex reactors do not work well DIY as you can suck stuff into the tank.

Check this link if you are woried about leaks.

http://www.plantedtank.net/forums/d...fied-mattenfilter.html?highlight=mattenfilter


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## Hoppy (Dec 24, 2005)

BlueRam said:


> Please do as you like as it is your tank.
> 
> Rex reactors do not work well DIY as you can suck stuff into the tank.
> 
> ...


Rex type reactors do work well with DIY. They don't suck anything. The CO2 is under a slight pressure in order to be driven into the reactor against the water pressure - the head of water from the tank down to the filter. But, they are a bit bulky.
The "reactor" that sucks is the venturi type, using a powerhead. A venturi creates a lower pressure at the "throat" which could conceivably be low enough to suck in the DIY fluids. But, a Barr type venturi type reactor does not, as I recall suck on the DIY bottles.
I don't think we are being asked for advice about whether to use the fluidized bed filter - a bad idea, in my opinion - but on how the arrangement with a CO2 reactor would work. I have no opinion on that.


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## tazcrash69 (Sep 27, 2005)

If you are worried about the look of equipment in the metal stand, you can either build a wooden facade, or take an easier route.

Have your wife pick out a fabic that she wants in the dinnning room, go to the craft store, and purchase the magnetic strip (comes in a roll of a couple feet). Have a helper hold the fabirc (wrong side out) against the tank. Use the magnets to secure the fabic to top of the frame, let fabric fall over the magnet hiding it, and the bottom of the stand. 

HTH,

BTW, just a quick chime in. IMHO With lots of stem plants, FBF (I did build one myself) is not needed.


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## exmt (Apr 11, 2006)

Okay, you guys have convinced me not to build a FBF. 

How about putting a handful of ceramic rings in the mech. module for a last stab at biological filtration? That way I could possibly get rid of that ugly HOB filter. 

tazcrash69, thats a great idea...I have some extra fabric left over from some window treatments that I would like to put around the tank. That'll get rid of the empty space and/or equipement. However, the mech. module is still going to sit on the shelf behind the tank.(the maxi jet can't pump that much head height if it was sitting on the ground.)

I am putting in mind the Rex Reactor, but when you think cost-mindedly, why buy extra plumbing parts when you have some spare sheet acrylic?

Thanks for all the help and input.


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## tazcrash69 (Sep 27, 2005)

Glad to be of help.

Ceramic rings = very good, I use them in my cannisters. The FBF is a bit overkill for planted tanks, and add extra complexity.



exmt said:


> I am putting in mind the Rex Reactor, but when you think cost-mindedly, why buy extra plumbing parts when you have some spare sheet acrylic


The only problem I can forsee with Acrylic vs PVC is that the acrylic has more joints, and thusly (why am I using this word?) potential for leaks.


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## exmt (Apr 11, 2006)

Oh yeah, not to mention trying to start the darned thing after a power outage..a canister filter would be much more reliable. 

Now about the possibility of leaks...This is my first time working with acrylic, so I really need to practice and be careful. I don't have a table saw, but I have a utility knife which I could use to score and snap the acrylic sheet. How would I glue the sheets together? I know that Weld-On is a common solvent cement. Could I just use some pvc cement or Gorilla glue?


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## tazcrash69 (Sep 27, 2005)

I had the same issue with my FBF when I shut it down for water changes. I think I had too much sand.

The last time I did acrylic work, I used a solvent purchased at the same place I bought the acrylic. Sorry don’t know the name, they re-bottled it.
Basically you put the 2 pieces together, use an applicator bottle (with needle applicator), apply a small amount to the joint, and the capillary action will draw the solvent between the pieces. In order to use the acrylic with solvent, you need perfect edges. I tried the scoring method, and unless you score all the way through, you won’t get that perfect edge without a lot of sanding, and then taking a chance on over sanding. If you are gong to do this, you should seal the seems from the inside with aquarium safe silicone. 

OK, without a table saw, I will definitely recommend the PVC route.

Seriously the PVC pieces are about $20 – 30 total, the work will go a lot faster, and be a lot less likely to leak. It may not look as slick as a clear reactor, but I value headache free parts, and if it’s in the stand, or behind the tank, who cares. 


Good Luck,
Walter


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## Anti-Pjerrot (Jan 20, 2006)

I know that you kan buy a special blade for cutting acrylic sheets, since i tried...

http://www.geocities.com/lfs2002sg/AcrylicCutter.jpg

Its SO easy to cut sheets with - i wouldnt recoment trying without...
You just use a ruler or something, to make a line, then you use this line, and draw 3-4 times with the blade (according to thickness) and the sheet will snap perfectly! No grinding needed!


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## exmt (Apr 11, 2006)

I have decided if I didn't have a table saw or solvent cements...well sheet acrylic is definetely not the way to go.

I still like the slick clear look(stubborn), so how about an acrylic pasta jar? http://www.lnt.com/product/index.js...o&doVSearch=no&pageBucket=0&parentPage=family
This one is $7.99 at my local store..

It is pretty tall, so it can hold a lot of media for the canister filter.

As for CO2, my current plans are to make a Rex reactor that hangs on the back. Should I put it before of after the flow of the canister filter?


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## tazcrash69 (Sep 27, 2005)

After the cannister because you don't want to gum it up with debris.


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## Anti-Pjerrot (Jan 20, 2006)

Well I used a syringe with araldite to clue with, using it like silicone. Its perfect.


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## Anti-Pjerrot (Jan 20, 2006)

knife?
http://www.geocities.com/lfs2002sg/AcrylicCutter.jpg


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## exmt (Apr 11, 2006)

Here is my new design of canister filter/CO2 reactor.

My concerns are:
1. Leaking? From where are likely places to leak? 
2. CO2 Rex Reactor effectiveness? I know that Rex did not use media in his reactor, but in a reactor this short, would media be needed?
3. Pump power? Will a Maxi-Jet 900 be able to power this assembly? It pumps 230 gallons per hour.

Thanks.


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