# Cleaning media or Tunze Bio Granovit



## Yo-han (Oct 15, 2010)

I'm using my Eheim Substrat Pro in my filter for over 5 years now. Although I never have any problems with NH4/3 or NO2 it seems the filter media is getting clogged. Now did I found a cheap offer for Tunze Bio Granovit and I was thinking about replacing the media bit by bit with this media, which seems to be about the same thing. I know Tunze is reef based so the marketing is as well, this is what is advertised:

Tunze Granovit is made from clay slag and is a highly porous filter material having a large surface area of 300 m2 / l. The grain size is 2-5 mm and it is pH neutral. A reduction zone is produced in the medium area of the granulate, in which the nitrate is degraded. On account of the fine pores, very high biological degradation activities are possible.

I know reduction is always happening deep in the biological filter media, but can I expect this media to be different from regular lava rock or my old Eheim substrat pro?

On the other end, does filter media indeed clog? Or will everything inside the granules get broken down eventually? And can I just rinse it very well to clean it, or use H2O2 (or anything else) to clean it?


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## niko (Jan 28, 2004)

Hey! It'd be interesting to see who can produce a reasonably smart response to your question. You are the #1 guru in filtration on this forum. 

How to suck ot the dirt accumulated in the zillions of tiny channels of the biomedia? Fair question. Funny thing I've never heard it asked before.


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## Yo-han (Oct 15, 2010)

Sucking them out feels like a dirty job, not good for your healthound:

Burning all accumulation away with H2O2 seems the best option to me (or bleach but I always prefer H2O2 because it only leaves water and oxygen behind). Replacing the media is more common (read easier) I guess, but I was curious. I think I'll experiment with some and check with a microscope this week.

About the Tunze, I know nitrate is degraded in every filter medium in the parts where O2 is depleted by the nitrosoma, nitrobacter and nitrospira. I do understand the high porosity is making it more active. But for my freshwater tank I don't want nitrate to be reduced too much. Can I expect more from this filter media than I can expect from a comparable media like Eheim substrat pro, or even regular lava rock?


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## Yo-han (Oct 15, 2010)

Have a satisfying and honest answer from Tunze regarding my question about the filter media. Though I share it:

The pores are very small compared to Eheim media or lava rock. This media is like a clay, imagine 3-4mm broken pieces of clay pots. With this small pore size the bacteria which break down nitrate can live inside and the surface bacteria use the oxygen so none gets to the anaerobic bacteria for the nitrate reduction. With a bigger pore, oxygen gets to these bacteria. Even so, it cannot be guaranteed any media will work for removing nitrate, some carbon must be present and the flow must be very slow. It would work as a bio media but is less efficient I believe than the Eheim media as an aerobic bacteria substrate. It has less surface. It is probably better than lava rock only because lava rock is not consistent, some is very good, most has many solid pieces and no pores.

Seems like they understand how a filter works, and it confirmed my doubts. Leaves the question whether you can open the media pores...


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## JeffyFunk (Apr 6, 2006)

As far as I know, all canister filters collect mulm and need to be cleaned... Isn't mulm the result of all bacterial decomposition processes? I tried the lava rock thing in my Eheim classics.... I wasn't impressed. As others have commented, the ADA Bio Rio also acts as a mechanical filter. I personally find it just as easy to use a separate course sponge filter in my Eheim classics as the mechanical filter - that's all I usually clean when I clean my canister filters. I've used lava rock, Seachem matrix, Eheim substrate pro and ADA bio rio. Other than the lava rock, I think they all work well (I think the bio rio does act as the best mechanical filter, though, but I don't have any definitive proof - only what I see when I clean my canister filters...)


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## Yo-han (Oct 15, 2010)

But do you simply rinse the dirt off, or is it possible to really clean the pores?


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## JeffyFunk (Apr 6, 2006)

Yo-han said:


> But do you simply rinse the dirt off, or is it possible to really clean the pores?


I simply rinse the mulm off of the sponges and give my biological media a good rinse now and then (like i said previously, it really doesn't get that dirty if i stay on top of cleaning my sponges or course filters).

Let me ask you a question, Yo-han - Why do you really need to clean the pores? Do you feel that it is really necessary or feasible to clean the pores of biological media (whether it be bio rio, substrate pro, matrix, etc)? What evidence in your aquarium do you see that would make you think the pores of the biological media are getting clogged?

As far as i know, i don't see any one suggesting or offering evidence that the pores of biological media need cleaning. From what i've read and seen in my aquariums, once the biological media is colonized and established, any decline in activity (as evidenced by rising N-NH3 or N-NO2 levels) can be attributed solely to a clogged filter where a rinse fixes the problem. I don't think i've read anywhere where rinsing the media alone did not fully restore the activity or function of the biological media and necessitate the use of more aggressive biological pore cleaning.

Besides, how do you think you'd clean the pores anyways? Bleach? Soap? H2O2? Water? I don't think bleach or soap or H2O2 sound like good ways to clean your biological media and how do you know water will clean the (microscopic) pores of the media anyways? Do you not think that the H2O2 will also damage the bacteria or other microscopic beings doing the cleaning?


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## Yo-han (Oct 15, 2010)

JeffyFunk said:


> Let me ask you a question, Yo-han - Why do you really need to clean the pores? Do you feel that it is really necessary or feasible to clean the pores of biological media (whether it be bio rio, substrate pro, matrix, etc)? What evidence in your aquarium do you see that would make you think the pores of the biological media are getting clogged?


I was interested in this because of the BBA in my tank. Organics can be broken down by bacteria, and although I never have NO2 or NH4 so those bacteria are doing their job, I thought that maybe I could improve the bacteria that reduce organics. So I was thinking about the biological filter media.



JeffyFunk said:


> Besides, how do you think you'd clean the pores anyways? Bleach? Soap? H2O2? Water? I don't think bleach or soap or H2O2 sound like good ways to clean your biological media and how do you know water will clean the (microscopic) pores of the media anyways? Do you not think that the H2O2 will also damage the bacteria or other microscopic beings doing the cleaning?


That was my second question. My best bet was H2O2. Doing it in parts, I have enough bacteria left to cover any nitrite etc.

So do people change their biological filter media periodically or never?


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## JeffyFunk (Apr 6, 2006)

Call me naive (and i totally admit it) but how do we know that biological filtration will remove organics? And what organics are we talking about? As far as i know, bacteria are not able to remove/eat/process all organics and are used mainly as a form of physical filtration and biological filtration to remove N based waste products like N-NH3 and N-NO2. 

(i'm guessing here that bacteria in canister filters are like the bacteria in compost bins - they will only remove easy to digest organic material and are unable to digest the harder, more complex/inert organic material like chitin, lignin, cellulose, hemi-cellulose, etc. In a compost bin, these materials are broken down by fungi.) 

Personally, If you want more organic removal, i think activated carbon would be a better choice. That's actually what i use in all of my planted aquariums. I've found that my java ferns don't get as much BBA on them since i've started using Seachem's activated carbon. I also found that my tap water isn't the greatest and activated carbon seems to be really good at polishing it up and removing the 'crap' from it. 

(I measured the total organic carbon in my water (TOC) and the value was very low (<5 ppm) but as far as i know, there is not enough data as to what level of TOC will cause an outbreak of BBA as the difference between my tap water and aquarium was only like 1 ppm TOC. Amano lists COD on the water parameters of some of his aquariums, but i don't like COD as a test method because it involves the use of Hg salts. (COD & TOC are related, but there is not a simple relationship between the two as they are very matrix specific.) Also, I have no idea how his COD packs work, but they can't be an official testing method as there is no method for COD in the Standard Methods book like his COD packs.) 

Also, random comment. Michael commented that his low-tech tanks (i.e. non-CO2 injected tanks) don't have BBA. If organics are causing BBA then i would expect non-CO2 injected tanks to not have an organic problem because the plants uptake organics as a carbon source. In a CO2 injected tank, the plants have no need to uptake organics as a carbon source (since CO2 is easier and more plentiful to work with) and so the organics have to be managed by either water changes or carbon... or both. 

Finally, i have yet to change my biological media. Granted, i've only been into planted aquariums for about 10 years now and have only had canister filters for about 5 years now, but still - i don't replace my biological media.


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## Yo-han (Oct 15, 2010)

JeffyFunk said:


> Call me naive (and i totally admit it) but how do we know that biological filtration will remove organics? And what organics are we talking about? As far as i know, bacteria are not able to remove/eat/process all organics and are used mainly as a form of physical filtration and biological filtration to remove N based waste products like N-NH3 and N-NO2.


Not calling anyone willing to discuss naive I know bacteria are able to process some organics, like urea. But as I'm reading up on organics, I don't know what types are present in our aquarium, nor do I know which ones cause algae and which are processed by bacteria.



JeffyFunk said:


> (i'm guessing here that bacteria in canister filters are like the bacteria in compost bins - they will only remove easy to digest organic material and are unable to digest the harder, more complex/inert organic material like chitin, lignin, cellulose, hemi-cellulose, etc. In a compost bin, these materials are broken down by fungi.)


Here a picture of some of the bacteria in our filters. As you can see cellulose is decomposed by bacteria although only in small numbers (log scale). In total, only 0.02% of all bacteria are nitrifying. Lots of bacteria left to decompose organics I would say, but haven't found any scientific info yet.












JeffyFunk said:


> Personally, If you want more organic removal, i think activated carbon would be a better choice. That's actually what i use in all of my planted aquariums. I've found that my java ferns don't get as much BBA on them since i've started using Seachem's activated carbon. I also found that my tap water isn't the greatest and activated carbon seems to be really good at polishing it up and removing the 'crap' from it.


Using purigen for a while now. They do color up so must be working. No reference though.



JeffyFunk said:


> (I measured the total organic carbon in my water (TOC) and the value was very low (<5 ppm) but as far as i know, there is not enough data as to what level of TOC will cause an outbreak of BBA as the difference between my tap water and aquarium was only like 1 ppm TOC. Amano lists COD on the water parameters of some of his aquariums, but i don't like COD as a test method because it involves the use of Hg salts. (COD & TOC are related, but there is not a simple relationship between the two as they are very matrix specific.) Also, I have no idea how his COD packs work, but they can't be an official testing method as there is no method for COD in the Standard Methods book like his COD packs.)


How did you test for organics? The only test I can find here is 'Salifert organics test'. Don't know how the ADA test works either. Always assumed incubation was needed for COD, or is this only for BOD?



JeffyFunk said:


> Also, random comment. Michael commented that his low-tech tanks (i.e. non-CO2 injected tanks) don't have BBA. If organics are causing BBA then i would expect non-CO2 injected tanks to not have an organic problem because the plants uptake organics as a carbon source. In a CO2 injected tank, the plants have no need to uptake organics as a carbon source (since CO2 is easier and more plentiful to work with) and so the organics have to be managed by either water changes or carbon... or both.


You say random, but I think this sounds very plausible! Will try to read up on that.



JeffyFunk said:


> Finally, i have yet to change my biological media. Granted, i've only been into planted aquariums for about 10 years now and have only had canister filters for about 5 years now, but still - i don't replace my biological media.


Haha, me too! When would you replace it? When it start disintegrating? Never?


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## JeffyFunk (Apr 6, 2006)

I tested for organics because i work in a laboratory. TOC (total organic carbon), CBOD and COD are all measurements for pollution but how they are done and what exactly they tell u is different in each case. In the case of TOC analysis, a sample is oxidized in the presence of a peracid to decompose organic molecules to CO2 gas. The gas is then purged and measured by IR. The advantage of TOC analysis is that it doesn't require the use of hazardous chemicals. The disadvantage is that it requires a TOC analyzer - something the average person will not afford or want. 

COD (chemical oxygen demand) is another measurement of pollution. A sample is added to sulfuric acid and the organic pollution is oxidized. In the official method, the oxidant is K2Cr2O7 - potassium dichromate in the presence of a mercury salt since halides are a known possitive interference (Hg salts react w/ halides to form a precipitate). The sample is heated in a sealed vessel and any pollution will be oxidized by the dichromate Cr(VI) to form Cr(III). The Cr(III) is measured by UV-Vis spectroscopy. The advantage of COD analysis is that it doesn't require fancy equipment. The disadvantage of COD analysis is that it requires the use of toxic chemicals and acids. 

Both methods are related but they tell you different things and are very matrix dependent. CBOD requires incubation for 5 days. That's all i really know about that test as i don't perform that test... 

The take home message is this - there are many to measure pollution and my one test was not conclusive. More tests would need to be done on many other aquariums by a standard method. Any accredited laboratory should be able to do the analysis - it's just a matter of collecting samples and doing the analysis and subsequent data analysis.


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