# Turning Koralia into a mini internal filter...



## NatureBoy (24 Mar 2013)

Think I've just pimped my powerhead...

I noticed that where my koralia 1600 is placed it has a tendency to drag water borne detritus through some willow moss, creating a rather ugly and inefficient storage of tank gunk that gets dispersed back around the tank through the powerhead when the moss is disturbed.

What I've done is cut and fitted a 1cm filter foam "jacket" around the powerhead and then covered it all in some 99p store tights (the type that makes great filter bags for carbon / purigen), the elasticated ankle fits snugly over the back of the koralia (could further fasten with a plastic cable tie)

It seems to be doing a great job so far of drawing in and holding the detritus dragged in and still creates a powerful flow down the length of the tank. Will up date if it seems to be working, as it could be a good way of mechanical filtering without adding anymore kit to the tank.

Is anyone else messing about with their tank kit on this cold crap grey weekend?


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## BigTom (24 Mar 2013)

Yeah I did a very similar thing when I ran my tank without a proper filter. I only wanted the koralia to provide very slow water circulation anyway, so I bought a block of filter foam that already had a hole cut down the middle and just wedged the koralia into that. Instant Hamburg mattenfilter.


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## NatureBoy (25 Mar 2013)

...and back again to plain old powerhead, after a day the flow had been cut by half I'd say making it not worth it.

That mattenfilter concept looks interesting for a non planted aquarium.


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## BigTom (25 Mar 2013)

NatureBoy said:


> ...and back again to plain old powerhead, after a day the flow had been cut by half I'd say making it not worth it.
> 
> That mattenfilter concept looks interesting for a non planted aquarium.


 
Low (or even no) flow is fine for low tech in my experience, assuming you've got sufficient filtration for whatever your bioload is.


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## dw1305 (26 Mar 2013)

Hi all,


NatureBoy said:


> That mattenfilter concept looks interesting for a non planted aquarium.


Mattenfilters are good for all sorts of tank. Because you don't clean the foam wall very often, you can plant the foam wall with ferns and also the top with a carpet plant like HC.

I had Java moss in my foam, but they ended up very "mulmy", great for browsing fry, but not particularly attractive.

cheers Darrel


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## NatureBoy (26 Mar 2013)

dw1305 said:


> Hi all,
> 
> Mattenfilters are good for all sorts of tank. Because you don't clean the foam wall very often, you can plant the foam wall with ferns and also the top with a carpet plant like HC.
> 
> ...


The concept seems interesting but all that mulm, and waste to be broken down surely puts a strain on the b.o.d? Also if I leave a filter foam to clog with the brown stuff then I can pretty much plot a graph of declining fish health. I like to mechanically gather up and remove the majority of the mulm with filter floss and rinse out / replace when maintaining filter performance, as I've found it seems to ease the burden on the mini ecosystem. Isn't a mattenfilter akin to a poorly maintained filter?

cheers


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## dw1305 (27 Mar 2013)

Hi all,


NatureBoy said:


> Isn't a mattenfilter akin to a poorly maintained filter?


Yes it is, but a very large poorly maintained filter. Because water flow is very slow through the filter foam it doesn't act as a mechanical & biological filter (like the foam in an external/internal filter would), but almost entirely as a biological filter.

You can think of it that the mattenfilter is much more like the live rock in a marine aquarium.

Have a look here <Hamburger Mattenfilter> & at Stefan Tanners "Swiss Tropicals" site:  <Poret HMF> & <Swiss Tropicals Fishroom>.



NatureBoy said:


> The concept seems interesting but all that mulm, and waste to be broken down surely puts a strain on the b.o.d?


No not really, mulm and faeces add very little BOD, they are mainly the structural carbohydrates etc that aren't easily biodegraded, that is why they accumulate. Ammonia, protein and sugars are the compounds that add to the BOD.

cheers Darrel


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## NatureBoy (27 Mar 2013)

dw1305 said:


> Because water flow is very slow through the filter foam it doesn't act as a mechanical & biological filter (like the foam in an external/internal filter would), but almost entirely as a biological filter.
> 
> You can think of it that the mattenfilter is much more like the live rock in a marine aquarium.


Cheers for emphasising this key difference - the slow flow changes things. It really is opening my eyes to the question of how effective a canister fillter really can be at biological filtration with the high flow rates through it. I'm tempted to buy a powerhead and put a mini gutter around my tank braces, put alfagrog in the trough and send water around it and overflow back into the tank - kind of a mini trickle filter type of water fall thing - low flow rate through the media. Have you ever done this, or improvised with filtration beyond canisters? I'm not overly worried with ammonia in my tank etc, as it's a jungle of plants at the moment, but it would be nice to experiment with the concept of filtration.

Cheers


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## dw1305 (28 Mar 2013)

Hi all,


NatureBoy said:


> I'm tempted to buy a powerhead and put a mini gutter around my tank braces, put alfagrog in the trough and send water around it and overflow back into the tank - kind of a mini trickle filter type of water fall thing - low flow rate through the media. Have you ever done this, or improvised with filtration beyond canisters?


I only recently started using canister filters, they are OK for biological filtration as long as you keep oxygen levels high, but they are much, much less efficient than a wet and dry trickle filter, and planted wet and fry trickle filters are another order of magnitude more effective and really are the gold standard of biological filtration.

cheers Darrel


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## dw1305 (28 Mar 2013)

Hi all,
I should also have said that:
I gave up on the over-tank trickle filters because people objected to the noise. When I had the system set up in the waste water lab. that wasn't an issue.

Additionally flow speed is relatively unimportant, a planted trickle system (and I would definitely go planted) will have an ever changing mix of aerobic/anaerobic zones.

If you look at "Hydrophyte's" riparium posts, you can see the kind of plants that he uses. This thread might also be useful: *Japanese Balcony Rice Paddy* <http://www.ukaps.org/forum/threads/japanese-balcony-rice-paddy-final-harvest.23151/#post-237645> and DeBryun filter <http://www.aka.org/UserFiles/File/debruyn_filter.pdf> and <Alfagrog for reducing Nitrates? | Page 2 | UK Aquatic Plant Society>

The anaerobic microbial out-gassing of N2 is irrelevant in planted tanks (this is in all our filters), so I like to keep things high in oxygen, and a high flow rate is one way of doing this.

I also like Clive's immortal description of a canister filter as a "pump in a bucket" <Rio 180 replacement | UK Aquatic Plant Society>, just remember that and you won't go far wrong.

cheers Darrel


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