# Biological Media....Please help?



## Holmesy

Hi Everyone. 

I know you guys specialise in planted tanks but i have some questions in regards to media in a non planted tank.

I need some help in regards to Biological Media choices. You guys have probably answered these kind of questions a 1000 times over but your be helping out someone who just wants to make sure they getting things right. Plus your all generally very helpful when it comes to things like this so i'm sure you won't mind helping me!

So here goes! 

I have 2 Fluval FX6'S that i'm going to be running on an ND 5ft tank and need some advice on the best biological media to use inside it. 

The top chamber will be mechanical and the bottom will have Purigen. so

Filter 1...... top - mechanical - middle - a form of biological - bottom -100ml bagged purigen

Filter 2....top - mechanical - middle a form of biological - bottom - 100ml bagged purigen

My FX6's came with cermaic tubes - which i have never used and just sitting the in the bags. What's your thoughts on using these? Someone told me they still have an impressive surface area of 6600 square feet! I just feel i could maybe be buying something better to colonise bacteria than the stock ceramic rings?

I have looked at Seachem Matrix and always thought it to be good stuff. However..reports circulating the internet and you tube is that Matrix is just pumice stone. Here is a video of what i mean:

http://www.youtube.com/watch?v=I7d3aK_tX34

I have contacted seachem on this and they haven't seemed to reply, so maybe they have been exposed as selling something at a super price for something that a pumice stone can do for dirt cheap. I don't for one moment deny Matrix works, but on the other hand i don't want someone like Seachem trying to pull my pants down and ripping me off.

The next biological media i have heard good things about is Biohome Ultra mini. 

Something that Richard aka Pond Guru from Tynevalley aquatics has marketed as being the very best media.
He does a wick test at 6.10 on the second link and you can see how quickly it absorbs! 
The last link shows Matrix on a wick test and it does a very poor job! it's £20 for 1kg - 1.40litres though and each fx6 chamber is 2L in capacity. So we are looking at over £40 here! plus it does clog up over time and needs replacing every 3-4 years. 

http://www.tynevalleyaquatics.co.uk/#/b ... 4573388508

http://www.youtube.com/watch?v=JFXJaRDfR1w

http://www.youtube.com/watch?v=1RBnw8Hqy7E

the next media i have looked at is Sera Siporax which apparently does not clog and does not need replacing and is a bit cheaper than the bio home boasting a surface area of 270m2 per litres.
It apparently has certain unique properties that make it one of the best bio-medias available. Here is what a friend sent me

"Unlike every other type of sintered glass media, it never clogs. This means it can maintain a high rate of gas exchange which is very important for the nitrification process. Similarly to Matrix, it can house anaerobic bacteria as well as aerobic. You'd need a much lower flow than is practical in a canister in order to successfully house a meaningful amount of said bacteria, but still, it's capable of housing them in the right set-up. various tests I performed on this media, one of them was using it as the sole filter media on a tank full of adult Mbuna. I employed no mechanical filtration whatsoever and the Siporax not only kept the water how it should be, it refused to clog"

Seems interesting and another option!

Apart from these top 3 then other one i'm looking at is good old Alphagrog, which i have used in the past but again like the rings i'm sure i could be getting better?

So what do you all suggest? I would love to hear your thoughts on all this. is there anything i have over looked? Should i pay out the higher prices?

thanks guys.


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## DrRob

Biggest problem I have with biofilters is them clogging. I can honestly say I've never had an issue where the filter wasn't man enough for the tank if the fish were stocked properly.

As a result, unless I'm going for ultrasmall footprints in filter, which I've rarely ever had to do then I've not seen the need to go beyond foam and alphagrog, with floss to polish.

As with any of these issues, there are 1001 different answers out there, and most of them are right.


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## Iain Sutherland

Same as above, 2x fx6 on 5ft is heavy filtering already so it will make little difference.   Just go cheap with Alfagrog or even better just use what you have.


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## dw1305

Hi all,


Holmesy said:


> My FX6's came with cermaic tubes - which i have never used and just sitting the in the bags. What's your thoughts on using these? Someone told me they still have an impressive surface area of 6600 square feet! I just feel i could maybe be buying something better to colonise bacteria than the stock ceramic rings?


Ceramic rings are fine, pumice is fine, floating cell media is fine, alfagrog is fine, hydroleca is fine, plastic pot scrunchies are fine ............


Holmesy said:


> Something that Richard aka Pond Guru from Tynevalley aquatics has marketed as being the very best media. He does a wick test at 6.10 on the second link and you can see how quickly it absorbs! The last link shows Matrix on a wick test and it does a very poor job! it's £20 for 1kg - 1.40litres though and each fx6 chamber is 2L in capacity. So we are looking at over £40 here! plus it does clog up over time and needs replacing every 3-4 years.


"_All I see before me is smoke and mirrors_". The problem with any discussion about biological filter material is that all literature and discussion produced by companies and salesman concentrates on factors that aren't really important, like absorbency and pore space, hence the wick test etc. and endless arguments about which media has the largest surface area.

None of this means anything in practice. 

You want a media which doesn't inhibit flow, the only real requirements are that the water flowing from the filter is still oxygenated, and that you have a large enough volume of filter material. I'll deal with the second factor first, and basically if you have a couple of handfuls of any biological media you have enough biological filtration capacity. The factor is the one no-one mentions in the great media debate is oxygen, but that is the really important factor. Siporax or EHEIM SUBSTRATpro are good media, but not because of their porous internal structure, they are good media because they are resistant to clogging.

I hope that helps.

cheers Darrel


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## Holmesy

This has been great so far

What's your thoughts on Matrix compared to the Eheim and Sera?


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## Henry

Lava Rocks 4 Litre


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## dw1305

Hi all,


Holmesy said:


> What's your thoughts on Matrix compared to the Eheim and Sera?


 I don't really have any, I've never used Matrix, and I wouldn't buy any of them (purely because of the price). I've used both Siporax and Substrat, because they came with filters that I've bought and they are both really good, and I'm sure Matrix would be good as well, but so are really cheap floating cell media and alfagrog. I would always have a sponge pre-filter on the intake (to keep out debris), and after that just 1/2 fill the filter with whatever biological filter material I had to hand. 

The best filters, in terms of their biological filtration capacity, were the planted wet and dry trickle filters (filled with hydroleca) we had in the waste water lab. They would  be an order of magnitude better than any canister filter.

cheers Darrel


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## Holmesy

Might just be worth sticking with what I got here then. Load of ceramic rings and a 2L tub of Matrix!


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## Alastair

Do you need mechanical in the top tray as the sponges around the edges are mechanical filtration anyway. Or did you mean floss media. 
Regarding the seachem matrix I used to have this and it didnt appear to look like pumice stone to Me. It was good stuff but now like iain I just use alfagrog. 
However the fluval bio rings will be ideal and are pretty good forms of bio filtration so why spend more money when you have everything already. 
In that video he says about the hexagonal media being fluval but ive never seen fluval media like that. You get g nodes or bio rings in fluval filters.  Both are excellent 

Save money and stick with the media supplied. 

Sent from my GT-I9505 using Tapatalk 2


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## justin85

The stock sponges on most if not all filters are course only, which means most small particles will pass freely through and end up clogging up the pours of the bio media. I always use 3 grades of sponge and floss in the first tray of my filters to remove as much waste from the water before it hits my bio media.


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## Holmesy

Seachem reply:

Hi Rob,

Thanks for your questions.  Don't worry about seeming picky or annoying; we love questions from hobbyist who want to understand more so they can provide the best environment for their aquatic critters.

Matrix certainly isn't the only biomedia you can choose.  Beneficial bacteria will grow on almost any submerged surface and people use everything from plastic scrubbing pads to the new sintered glass media like Biohome Ultra.  Each has pros and cons, and can be judged on a few critical criteria to choose the best for use in our filters.

The first consideration is going to be surface area.  The greater the surface area, the more bacteria that can colonize the biomedia. Providing surfaces to colonize is the main job of any biomedia.  Second we have to consider what kind of surface area the biomedia provides: internal or external?  A biomedia like bioballs increases surface area for bacteria to colonize, while allowing water to flow freely through it, but all of the surfaces are external; aerobic nitrifying  bacteria can grow quite well on them, but can easily be disrupted if rinsed or exposed to air for too long.  Porous biomedia like Matrix or any of the stone, ceramic, or sintered glass media are going to also have some internal surface area.  This will increase the available surface for bacteria colonies while also providing some protection to them against being washed away or dried out during filter maintenance.

 The size of the pores in the medium is also important.  The larger the pores, the smaller the surface area.  In the other direction, if the pores are very, very small; then the surface area might be great but then won't work as well as a biomedia because of bacteria not being able to grow in the small volume inside the pores and the decreased efficiency of fluid transport.  As noted in the study and described on the Matrix product page, all of the compared biomedia had pore diameters in the range to be biologically useful, but Matrix had 4 to 9 times the biologically active surface area compared to the other media. We haven't tested Matrix against Biohome Ultra (or any of the other Biohome media), but both Substrat Pro and MicroMec are also sintered glass media so I suspect the comparison would be similar.

Another consideration is durability and maintenance.  Matrix is an inert, porous stone which is extremely durable, and because most of the surface area is internal, it can be rinsed without destroying all the beneficial bacteria.  One issue that I've seen mentioned online about sintered glass media is that they can be worn down over time and need replacement; unless you have your Matrix in a rock tumbler, it isn't going to breakdown.

One of the advantages of Matrix versus many of the traditional biomedia is that the densely porous interior space allows for anaerobic denitrifying bacteria to colonize and remove nitrates.  The Biohome Ultra claims to be able to also support these colonies based on the same principle. Looking around for more details about it on the web, I see people saying that it needs to be used at a lower flow rate to support denitrifying bacteria and works best in lower light levels.  In comparison, Matrix can support denitrifying bacteria even in high flow situations and works fine even in well lit conditions.  The wick test might provide a clue as to why this would be true: the quick wicking of fluid through the Biohome suggests that water can penetrate deeply into it quickly.  In a high flow application, this would make it likely that more oxygen would make its way deeper into the media, supporting aerobic bacteria but potentially making it more difficult for anaerobic denitrifying bacteria to survive. 

There are other good biomedia on the market, but Matrix has stood the test of time and works exceptionally well.  While it is easy to set up visual comparisons like the wick test where other media appear to out-perform it, or to hold it up next to media which look more manufactured and deride it as just a bunch of rocks, the proof is in its performance in the aquarium.  I understand why people look at it and compare it to the pumice they can find at the garden center; they are both porous stones.  The difference is that not every porous stone is the same; Matrix is a specific type chosen for its porosity, pore size, durability, and inert nature.  When you buy Matrix, you know what you are getting.  It has been tested in the lab and in thousand of hobbyist's aquariums for more than a decade with excellent results. 

I hope this answers your questions.


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## ceg4048

Also, pot scrubbers and alfagrog have been tested by thousands of hobbyists and has stood the test of time. Please review post #4 of this thread. All you need to know is in that post.

If you have problems with water discoloration then any of the popular products such as activated carbon or Purigen can be added.

Did you really think that the company that sells you overpriced goods would have answered your question in any other manner?

Cheers,


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## dw1305

Hi all,


Holmesy said:


> Matrix certainly isn't the only biomedia you can choose. Beneficial bacteria will grow on almost any submerged surface and people use everything from plastic scrubbing pads to the new sintered glass media like Biohome Ultra.........


It is quite a clever answer, and a lot of it is scientific fact.


Holmesy said:


> The larger the pores, the smaller the surface area. In the other direction, if the pores are very, very small; then the surface area might be great but then won't work as well as a biomedia because of bacteria not being able to grow in the small volume inside the pores and the decreased efficiency of fluid transport. As noted in the study and described on the Matrix product page, all of the compared biomedia had pore diameters in the range to be biologically useful,........


But then we get onto pore space, and it starts to unravel. Whether a pore space is biologically active or not is going to depend on all sorts of factors. In some systems, such as ones with a large bio-load, we don't really want any fine pores, they'll almost instantly clog.

It is a bit like a lawn mower manufacturer saying "_my lawn mower is much better than any-one else because it has more blades and can cut much lower to the ground"_ they then go out and compare theirs and their competitors mowers, on their test bowling green, their mower is the best one by a mile and their claims are "proven". The next manufacturer then comes up and says "_no, your lawn mower isn't the best, ours is_" out they go out to their test lawn, which is 15cm long, bumpy and on a slope, their petrol powered rotary mower does really well, whilst their competitors is a genuine non-starter, again point "proven", the second mower is the best. Then a third company comes up ...........


Holmesy said:


> One of the advantages of Matrix versus many of the traditional biomedia is that the densely porous interior space allows for anaerobic denitrifying bacteria to colonize and remove nitrates. The Biohome Ultra claims to be able to also support these colonies based on the same principle. Looking around for more details about it on the web, I see people saying that it needs to be used at a lower flow rate to support denitrifying bacteria and works best in lower light levels. In comparison, Matrix can support denitrifying bacteria even in high flow situations and works fine even in well lit conditions. The wick test might provide a clue as to why this would be true: the quick wicking of fluid through the Biohome suggests that water can penetrate deeply into it quickly. In a high flow application, this would make it likely that more oxygen would make its way deeper into the media, supporting aerobic bacteria but potentially making it more difficult for anaerobic denitrifying bacteria to survive.


And now they are both trying to confuse and kick the opposition whilst they are down. *We don't need anaerobic de-**nitrification, even if it works as claimed, we have plants, and plants use NO3. In fact they use it to the extent that we have to add it* *to our tanks. Levels of NO3 go down in our tanks, not up.* So in this case if the comments are true it is a big plus for "BioHome"and an own goal for Seachem.

We also have a substrate, where all sorts of interesting things will happen. These are the words of the "Skeptical Aquarist" <Substrate | The Skeptical Aquarist> &<De-nitrification | The Skeptical Aquarist>, who I can't recommend strongly enough.


> The third function of the substrate is to offer a vast range of colonizable surfaces for a diverse community of bacteria some of which are the agents of biofiltration, together with water-filled interstitial spaces of varying scale. The aerobic bacterial communities that metabolize ammonium to nitrite and then to nitrate have been a well-known feature of the substrate since the introduction of the undergravel filter in the 1960s. But sometimes people don't seem to realize that for every free-floating bacterium in the water column, there are hundreds of thousands settled in the biofilm, efficiently metabolizing one another's waste products. ............Researchers have determined that the mature biofilm on stem and leaf surfaces of water plants, which are substrates for bacterial nitrification, are also locally coupled with de-nitrification. The nitrifying process is stimulated in daylight by the oxygen diffusing from photosynthesizing surfaces, in a gentle diurnal pulse that only lab experiments can detect. The uppermost surfaces of the substrate are also prime locations for these biofilm populations, as you know.
> 
> The nitrification process demands a lot of oxygen, more even than familiar cellular respiration. Only a few millimeters below the substrate's surface, or in the interstitial water of a mature biofilm, the diffusion of oxygen can't keep up with demand. As localized oxygen levels drop in a gradient, facultative anaerobic bacteria find their niche. "Facultative" in this sense merely means "opportunistic." Many ordinary bacteria are facultative anaerobes: when oxygen is in short supply, these kinds of bacteria are able to switch to a metabolism that doesn't require oxygen. Instead, some use nitrate. The familiar nitrating bacteria provide the nitrate, and their high oxygen demands also tend to exhaust the limited supply. So besides providing the nitrate, a thriving microzone of aerobic nitrifiers provides low-oxygen conditions too. You can visualize a mutually beneficial exchange between the two types of bacteria across a fluctuating boundary lying not far beneath surfaces. If there were no other reason not to disturb the substrate in an aquarium, this would be enough for me.
> 
> If plants are well-rooted in your substrate, their rootzone (_rhizosphere_) provides further edge microzones for de-nitrification. Oxygen transported through the vascular system of stems and roots diffuses into the spaces adjacent to each rootlet, supporting surrounding microzones of nitrification. Just beyond this aerobic network, in hypoxic porewater, bacterial de-nitrification occurs. .


Cheers Darrel


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