Nitrification filter materials

justin guest

Feeder Fish
MFK Member
Jun 6, 2008
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I just wanted to share my experiences of different filter materials often used in the aquatics industry. I won´t go into detail with all filter media types available but try and keep it simple so beginners also have a chance to conceptually understand what i´ve written.

A couple of guidelines before I start;

-The most important guideline - I´m not looking to rewrite the book on filtration so please don´t take this information out of context. I´ve seen identical systems react completely differently sometimes so I expect that many of you will have experience contrary to what i´ve written here.

-Not all of my observations hold for marine systems so with regards to saltwater please - don´t quote me on that!

-All of my observations include experiences made with recirculation systems as well as single aquaria and ponds.

-All of my observations include experiences made with systems running at temperatures from 2 degrees celsius/35.6 degrees fahrenheit (yes nitrification also occurs at such low temperatures) up to 35 degrees celsius/95 degrees fahrenheit

-All of my observations include experiences made with wet (immersed filter material) , wet/dry (filter material immersed and in a trickle tower) and pure trickle tower systems

-Hardness and Ph as well as other water parameters are variables which can change the performance of different filter materials in relation to each other but in general what i´ve written works for most water types. Extremely hard water can lead to coating of filter materials with calcium deposits which will drastically affect the biological capacity of the given filter material

So here goes...



Filter material half life

All filter materials including plastic materials which are supposed to have a high microscopic surface area become polished after a while so in the end one type of filter media is just about as good as another for a given macroscopic surface area. This happens because the colonies of bacteria actually smoothen the surface of microscopically rough surfaces. I worked for years together with a french recirculation systems company who had their filter media in trickle towers analysed regularly. All Bioball types used for instance, lost microscopic roughness at the latest after 5 years. This means you should also partially change plastic medias every couple of years (not just stuff like efisubstrate) if you need high performance from your biofilter. I understand that different media types have widely differing surface areas and I am not trying to spark a debate about which is better but state the fact that ALL filter materials even ceramics, sand and scrubbies :) reduce in surface area over time.



Nitrification rates of different filter materials

Unless mentioned I´m assuming ammonia/nitrite and nitrite/nitrate conversion patterns in relation to time and temperature follow the standard patterns as documented in filtration literature (also known as cycling time).

Sand;
The most stable filter material in relation to biological loading is sand. A swimming pool sand filter is better than a fluidized sand bed filter due to the fact that a fluidized bed often needs longer than normal to cycle. An added danger when using a fluidized sand bed filter is when the pump dies. With a fluidized bed 98% of the bacteria die within 1-2 hours due to oxygen deficiency when the fluidized bed falls in on itself. In contrast with a swimming pool sand filter you have at least half a day before 98% of the bacteria die. Don´t forget to backwash the swimming pool filter before starting it up again. Don´t get me wrong though, a fluidized bed when it´s running can be a fine thing and offers the best nitrification rates per volume of any filter.
Due to high energy and water needs a swimming pool sand filter won´t be the ideal choice for a lot of people but if you do want to run a swimming pool sand filter then the best quality water (mechanical and biological) will be achieved by installing the filter in one of two ways. Firstly by running a small pump to filter and a large pump to backwash, or secondly the alternative that i prefer is running two pressure chambers parallel behind a pump that would normally be rated for one of the chambers to filter with, and then backwashing the chambers one at a time with the full power of the pump. With both methods the sand won´t become compacted and the water will be extremely finely mechanically filtered due to the slower flow rate in the chamber during filtration.
Both fluidized and swimming pool sand filters are biological workhorses when up and running but have issues which is why sand isn´t as widely used as a biological filtration medium even though it does an excellent job.

Biohome;
I never had any unusual problems with nitrification when biohome was used in the systems - I´m not a biohome fan, that´s just the way it is.

Siporax;
My experience with Siporax is that it lowers ammonia levels nicely but often needes longer than usual to start lowering nitrite levels. In some systems nitrites were still present after 3-6 months.

Bioballs;
To a lesser degree the siporax phenomenon also occured with bioballs in trickle towers. I solved the problem with both filter materials by adding foam into the filter systems which brings me to the next point...

Filter foam;
After sand, filter foam gets second place on the effectiveness list as i´ve noticed that it cycles very quickly and that from all man made materials nitrite/nitrate conversion works best when using filter foam - wet or dry! Fine foam clogs too quickly as a biological filter media but a coarse foam sheet set perpendicular to flow BEHIND the fine particle filter stage (wet or dry) only needs light cleaning every 6-12 months if at all. You can also set course foam cubes (stacked irregularly) before the fine filter stage but i´d only recomend this in a trickle filter setting due to clogging and dead zones when done immersed. That said foam alone is sometimes sensitive to ammonia spikes (new fish delivery for instance) when used immersed so bioballs, sintered glass or ceramic materials can be used in combination with the foam to solve this problem. As a result of my experiences I then helped a pond filter company in Germany to design a filter media which consisted of a siporax ring with a foam ring pushed over it. This media hardly needs cleaning and is extremely stable biologically. if anyone is interested the media is called combibac

see http://www.genesis.de/

You will have to translate the site through google though.

Scrubbies;
I have no experience with this filter material but the principles of using scrubbies seems sound. Lots of people on this site go nuts about them but it would not surprise me to hear that some people have experienced long cycling times in relation to nitrite/nitrate conversion. could be wrong though.

Japanese matting;
Japanese matting is overrated. I´ve been travelling to Niigata in Japan for years and can tell you the Japanese Koi breeders use this material because it´s cheap and they have lots of space for filters. In an aquarium setting i´d only recommend this material as a first mechanical filter for plant leaves etc as its actual surface area per volume is way behind other materials and it often needs a longer cycling time. The Japanese only like it so much because it doesn´t clog easily

Gravel;
Biologically an excellent material but there are cleaning issues whether used for an undergravel filter or placed in a filter chamber.

Others;
I haven´t tried to make this an exhaustive list so if i´ve left out any other important filter materials feel free to fill in for me.


Mixing filter media

One thing that i see very little written about on this site though is about the importance of combining different filter materials in one filter chamber (forgive me if i´ve missed a post on this). The number of surface loving bacterial species in a filter qaudruples as a rule each time a new filter media type is added due to a reduction of species dominance. This is due to the fact that certain bacteria like certain surface types more than others. If you have different surfaces then no one species can become and remain dominant. A wider range of nitrifying bacteria species also means the filter becomes more biologically robust. It isn´t that important exactly what filter material you use (given that surface area isn´t too bad for a given filter material) but extremely important that you mix your filter medias - not layered like we aquarists love to see but mixed up with each other in the same chamber the way mother nature likes it


Well there you have it - my two cents worth. hope it helped

j<><
 

Dr Joe

Feeder Fish
MFK Member
Mar 8, 2006
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:mwave::welcome::mwave:

Well put.

Your findings fall directly in line with what can be found on this site so you shouldn't have any controversy here :D.

Getting people to mix filter materials has always been a problem (looks like you don't know what your doing to the uninformed).

Some materials can be rejuvenated to an extent(except sand) by tumbling with fresh silica sand (sharp edges). Works best on plastics, and to a lessor degree on ceramics (ceramics claim to such high surface areas is due to holes (which don't have circulation anyway) in the material that clog with bacteria which can't be cleaned out.

When you remarked about testing with trickle filters, were these the hobby industry standard of 18" or less? Or like some of us that have 5ft - 10ft towers?

I wish I could comment further, but since I'm in agreement with your findings it's difficult ;).

Thanks for posting your finding and we look forward to your future posts.

By the way what tanks / filters do you have up and running now? Feel free to post pix too.

Dr Joe

.
 

justin guest

Feeder Fish
MFK Member
Jun 6, 2008
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To give you an idea of what systems i´m talking about maybe a bit of background info would help. Up until last year I had been working for the previous eight years at a large german pet shop chain called koelle zoo

see http://www.koelle-zoo.de/

I was in charge of designing (technically and aesthetically) and supervising the building of the new shops and refurbishing the old ones. I was also in charge of the pond section of the business (the niigata trips). Due to a degree in aquaculture (which doesn´t exist at the uni level in Germany) I was able to teach the germans in the company a thing or two and help save thousands of fish from simple filtration mistakes. Over the years i´ve overhauled all of the systems in the business which gave me a fantastic opportunity to experiment with the effectiveness of different technologies. One thing the Germans do have is a weakness for complicating things. I stuck to the principle of KISS (keep it simple stupid) and managed to overt a few disasters. The experiments with the trickle towers were recirc. systems with an average of 200 aquariums per system with a turnover rate of approx. 4 times an hour. The capacity of the towers were around 800L/200gal. Some of the towers in the saltwater recirc. systems were only about 200L/50gal though. My further experience was also with Block filtration (1000L/250gal) systems where certain groups of fishes needed specific water types. The block systems were seldom run with towers due to space considerations but to compensate the oxygen issues I ran the systems with average turnovers of 8 times an hour. I also installed further towers on a lot of the ponds with an average tower volume of 400L/100gal. The sandfilters were used for display tanks up to 10000L/2500gal and for the mechanical filtration on the ponds we installed paper filters (see the genesis link in the original posting). Small trickle towers like most people use were reserved for small show tanks up to 1500L/400gal but i never did any hard research on these systems. Above 1500L/400gal I always installed more robust mechanical filters (sand filters).
As for my own systems i only have an 800L/200gal tank at home as I´ll be going back to Australia next year. The system is running on a large eheim canister filter. At the moment i´m running mixed tropicals but must admit I´m a clown loach fan - my current clown loach collection is 33 fish up to 25cm/10in. I´m also running about 150 other fish in the tank but wouldn´t recommend this stocking density for beginners. When back at home I´m planning to build a 15000L/4000gal tank to hold a mixture of peaceful fish including Aussie natives. As for photos i´ll have to search around a bit first. Any other questions I´d be happy to answer.
P.S. thx for the welcome
j<><
 

frasertheking

Fire Eel
MFK Member
Feb 17, 2007
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great info mate i found the bottom part on mixing media very interesting as i have never considered this. :headbang2
tank looks great fish looks great welcome and i hope to see more interesting info from you in future :popcorn:
 

justin guest

Feeder Fish
MFK Member
Jun 6, 2008
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Australia
Thx. I´m thinking of doing a thread on UV sterilizers as well... the practical aspects not the theory. A lot of people don´t seem to know how to use them optimally. I even had to get phillips check some of their uv replacement lamps once cause they weren´t living up to expectations! As for the media mixing i´m happy if it helps you to achieve better water quality
j<><
 

OscartheGrouch

Feeder Fish
MFK Member
May 2, 2007
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Nice. Great looking shoal of clowns in your tank and all that activity looks amazing as well. :)
 

justin guest

Feeder Fish
MFK Member
Jun 6, 2008
485
0
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47
Australia
OscartheGrouch;2014033; said:
Nice. Great looking shoal of clowns in your tank and all that activity looks amazing as well. :)
Thx. When watching tv the clowns often come to the couch end of the tank and watch tv as well!
j<><
 
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