DIY FBF/tower filter

[ILLUSN]

Hi all thought I'd put up a quick DIY on some of my ugly but very effective filters.

These filters are strictly BIOLOGICAL filtration only, so please keep that in mind if your thinking of adding one to your tank.

heres what you need to get started.

1x 90mm PVC drain water pipe (length dependent on your tank height)
1x 90mm drain water pvc T
1x 90mm endcap
1x 90mm-40mm stepped reducer
1m 40mm PVC low preassure pipe
1x 15mm high preassure PVC pipe(same length as your 90mm)
1x 15mm high preassure T
1x15mm high preassure 90 degree elbow
1x 15mm faucet adapter with male thread
1x 15mm ball valve
1x 19mm barb to 15mm male thread irrigation fitting.
acetone
cordless drill with 5mm bit
hacksaw
teflon tape
PVC glue

[ILLUSN]

next up take the 40 mm pipe the 90-40 reducer and the 90mm T and assemble as shown

[ILLUSN]

take the assembled body to the tank and size it up just to make sure everything is at the right height.

then its time to start the water inlet pipe.

[ILLUSN]

drill holes in the side of the T to allow water to flow better into the filter

[ILLUSN]

If your using a pump with adjustable flow controle you can leave out the ball valve saving you $5 and just use the barb onto a female faucet adapter.

either way you'll need a little 15mm pvc to join the manifold to the 90 degree 15mm elbow with joins to the pipe that runs to the base of the filter.

[ILLUSN]

now for the media, the idea is to attain a fluid state of substrate in the filter so ideally you'll fill the filter to 1/2 way with sand and allow it to rise to 2/3-3/4 up the column when "fluidised".

if your running a high flow pump a heavier media is better so as you dont get sand entering the tank. pool filter sand works well here.

as the principle behind this type of filter is slow flow massive surface area a finner sand like silver sand will give more biological activity but to use this sand you need a slower flow rate.

[ILLUSN]

put a few handfulls of nice corse media at the base of the filter like big ceramic rings, then add you sand, if you use poolfilter sand wash it first silver sand is clean from the packet.

fil the filter to 1/2 way then turn on the pump adjust the flow so as no sand leaves the filter

[ILLUSN]

these filter have excellent biological capacity, 2L of sand is plenty to filter your moderately over stocked tank, as the sand bumps into each other it self cleans itself and you'll often see a mulm develop on the surface that is easily removeed with a small siphon.

These filters do have their problems, they have no mech filtration at all so need pumps with good prefilters, failure to do this results in muck getting trapped in the sand bed and eventually leads to ph crashes as the muck rots and turns to nitric acid.


eventually you will have to remove all the sand and give it a good clean in tank water, mine lasted a good 6 months before i had to do this. cleaning the sand is a pain you might be better off just replacing 3/4's of it.


Also after a power cut the sand can settle and compact, this is less of a prob with pool filter sand. when the power comes back the pumps can fail to have the preassure to re fluidise the sand bed, fitting a 15mm non return valve would help fix this problem.

I've since modified all my pvc FBF's to now be matrix tower filters. It allows me longer intervals between cleans and i dont have to worry about the sand bed compacting, they dont have the same biological capacity but for a total build cost of under $30 they're a cheep reliable canister filter. the best thing about the design is you can hook it up to anything as seen below i've got it hooked up to an eheim univerdsal 1200l/h pump using a dead 2017 as a prefilter (corse sponges and ceramic noodles).

[ILLUSN]

you can also make these things as big as you like my biggest is a 2m tall unit hooked up to my 6x2x2 running on 8L of matrix.

Water is pumped via an eheim compact 1000 up about 30cm of 16/22mm hose then into 15mm pvc pipe down to the bottom of the filter, here it rises up through 8L of matrix before cascading back into the tank, the flow rate is low only 650L/h, so it turns the tank over once an hour, this filter has reduced nitrate in my system from ~40ppm to below 20ppm.

the tank gets top ups once a week to replace water from evaporation and a proper clean and 50% change every 6-8 weeks.

http://www.discusforums.com/forum/files/dscf4007.jpg

an eheim pro 3 2080 is also running on the tank and its densly planted

[poddan]

A monster filter :D

Not so easy to clean?

[ILLUSN]

It's not as bad s you'd think, basicly i just take it outside and up end it ito a 20L bucket and give the media a quick once over with a bucket or 2 of tank water.

as the media is matrix it washes clean easy, with sand its much harder, hence the switch to matrix.

[poddan]

For 30 $ it must be worth building this.

About the media, could other media work just as good?

[ILLUSN]

Any media will work i just use matrix because its maintanace free, you could use any media that sinks, scoria would work well and costs nothing ($8 for 20L) but it will take forever to wash clean.

[xrboy_85]

Hey Jothy

awesome idea mate!! do you think this would work if i plumbed it up to my fluval404 outlet that is rigged up to that new max mix c02. will the co2 hurt the matrix in the pipe filter???

Tia Justin

[ILLUSN]

MATRIX is volcanic rock its inert and wont be hurt by CO2. you could hook it up to the outlet of your fluval if you wanted to, the fluval would work as an excellent prefilter.

the only problem is as water tunbels out of the pipe filter it will loos co2 if it breaks the waters surface. to get around this add a short length of 40mm pipe from the exit of the pipe filter below the surface of the tank, just like my big filter.

[xrboy_85]

Awesome

here we go!! Bio capacity is about to ski rocket
Thanks Justin

[Ghoti]

I've been pondering this approach for some time - to me it seems an excellent (and cost effective) way of improving filtration capacity.

Sure its easy (but expensive) to simply add another canister, but that brings with it additional flow to disperse in the tank.

On the other hand, driving this style of filter off its own pump gives redundancy and perhaps lowers cost, but doesn't address the flow. And to be honest, I really don't like the idea of a meter of stormwater pipe taking up residence in the lounge. . .which caused me to ponder more.

Am I correct in thinking that the pump is really only needed to lift the water to the tank and its primarily the extra volume of filter media that provides the benefit, rather than the way its arranged (vertically)?

My current thought is to use similar principles to this design, but using a 15lt screw top water-tight food-safe container (costs $17) that would fit in my cabinet. By removing the tap bung I could plumb the "spray bar" in the bottom, connected to the outflow from the tank. I could then use some filter sponge in bottom and top with other media sandwiched in between. A through-hull fitting from BCF would be the top outlet.

The siphon-effect would draw water from the tank, through a pre-filter (e.g. sponge in a short section of 90mm pipe), then to the FBF. Upon exiting the FBF it would flow into my canister filter for a final filter before being pumped back into the tank.

Would this a) work and b) provide a significant improvement in filtration?

As far as FBF filter media, I expect I'd need something heavier than sand as I don't have gravity working as well as it would in a tower. Perhaps matrix, or even commercial pot scrubbing pads as used in some DIY pond filters.

Looking forward to your thoguths.

Cheers,
Scott

[ILLUSN]

A few issues with your concept if you use a siphonic flow into the diy filter you'll have to be doubly sure there are no leaks also if you filter the water before the canister your better off just using mech media and filling the canister with bio media. This brings another issue of cleaning usually it's easier to clean a commercial filter then a diy one. A better approach would be have the water go through the canister first then have the clean water go through your diy filter full of matrix or other biomedia. This way the canister does all the mech filtration and most if the bio filtration in the process it consumes most of the oxygen in the water, your diy filter then finishes the the bio filtration and begins removal of the nitrate. If you have room under your tank your best off using a sump and the using your canister( with bio media only) as a return pump

[Ghoti]

A few issues with your concept if you use a siphonic flow into the diy filter you'll have to be doubly sure there are no leaks also if you filter the water before the canister your better off just using mech media and filling the canister with bio media. This brings another issue of cleaning usually it's easier to clean a commercial filter then a diy one. A better approach would be have the water go through the canister first then have the clean water go through your diy filter full of matrix or other biomedia. This way the canister does all the mech filtration and most if the bio filtration in the process it consumes most of the oxygen in the water, your diy filter then finishes the the bio filtration and begins removal of the nitrate. If you have room under your tank your best off using a sump and the using your canister( with bio media only) as a return pump

Thanks for that. Now off to read up on sumps!

Cheers,
Scott

[jackleaon]

Its interesting we can build biological filter. So its cheaper and we don't have to spend money to call mechanic to repair it. But I think it will not that much effective. But i will definitely try this one.

[Hooked]

Hi, a great read from beginning to end! I love the simple design. You have really got me thinking. Running the inlet pipe back into the tank, just below the surface would probably cut down a bit on the water splash noise also? I started out with tropical fish about 6 months ago, got into Discus about 4 months ago (been on a steep learning curve!) and have gone from a 4 foot, to a 6 foot and now setting up a 8.5ft 1100lt display in the lounge. I have just bought a Eheim 2080 and was thinking of buying another one in the near future to have a decent amount of filtration once the tank starts to fill with stock. At $800 with media, they are not cheap. This is a great area to save some money and end up with a very useful and satisfying filter addition. Just need to come up with a way to disguise something like this that keeps the wife happy...hmmm, maybe try and place it behind the tank and plumb through the back of the hood?
I find myself looking up large acrylic tank builders in China, out of interest, on the net in my breaks at work. Where will the madness end....... : )

Cheers

[swifto]

it never ends. :twisted:

[ILLUSN]

LOL