# Filtration in NPTs is it detrimental?-post a pic of your tank for comparison



## SBS (Feb 26, 2013)

Hi all. There was a debate recently whether biofiltration is beneficial or not in NPT tanks. Some think a lot of bio filtration is bad, some think one can do without, some think a lot of bio filtration is beneficial.
*I would like to invite everyone to post a picture/video of their tanks* and list the major parameters. It's hard judging by a picture and the success of a tank depends on many factors but at least we can try and debunk a few theories in regards to filtration in NPTs.

I am one of those that think that filtration and flow in NPTs is desirable for many reasons.

Here are the specs of my NPT tank:
Filters and tank were setup since February, but soil, plants and fish went in around April.
Soil-mineralized topsoil mixed with red clay, capped with coarse sand.
No fertilization or CO2 of any sort added.
Size: 100G
Filtration: About 1120 G/H in total making up for over 10x bio filtration between:
1xExternal-528G/H-filled with coarse sponges and ceramic rings
1xExternal-264G/H-coarse sponges and ceramic rings
1xFluidised Sand Filter-powerhead 330G/H

Other specs:
Light-135W High Power LEDs-suspended
Fauna: 20-ish red wag tail platies, 30-ish corys, bristlenose pleco, otto, red cherry/red rili shrimp, all types of snails: MTS, red ramshorns, pond snails...
Flora: too many to list..

The picture is the latest I have and I had trimmed a lot of the stem plants but it gives an idea.









The tank from today 29th Sept. Please excuse the low water level. This is because I fixed a leak last weekened and I've been afraid to fill it to the top. The shape of the plants got knocked because the tank stayed less than half full for 2-3 weeks and I only fixed it less than a week ago.









Short Video:





Notes: I am not good in aquascaping but besides that the tank never developed an algae problem, the glass has never been cleaned, water is very clear and there's no surface scam of any sort. I've tested nitrAtes twice and barely got a reading but I don't trust these tests much anyway. I measure the TDS instead and do a water change every 2-3-4 weeks depending on the result.


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## frenchie1001 (Jun 25, 2013)

i am on the pro filter side. this tank has been set up for about 3 weeks so its pretty early to tell.

specs
120gal
ehiam 2217
fluval 205
kinda mineralised top soil w/sand cap
some root tabs are the only ferts.

at the moment there are 6 cories, 10 glow lights and 10 hengals rasbora's in there. i havent had any algea's issues so far but have some pretty crazy diatom coverage at the moment.



this photo is about 2.5 weeks old.


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## Zapins (Jul 28, 2004)

Perhaps I have missed a lot of threads on this topic but I wasn't aware that there was an ongoing debate between NPT people where some recommended no filter over having one?


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## SBS (Feb 26, 2013)

There were a couple ongoing threads in regards to filtration in NPTs. It seems that there's an understanding that having a filter in an NPT tank is going to have a bad effect on plant health. 
Some people thought it's a good idea opening a thread about it and just show examples of one or other scenario.


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## Zapins (Jul 28, 2004)

Link to the threads? Was it on another forum?


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## SBS (Feb 26, 2013)

It comes from these two threads on this forum.

http://www.aquaticplantcentral.com/forumapc/el-natural/89001-setting-up-120g-npt.html

http://www.aquaticplantcentral.com/forumapc/el-natural/89000-reducing-bio-filtration.html


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## Zapins (Jul 28, 2004)

Honestly after reading through those threads I don't think it is much of a debate. I think it looks more like a couple of people have taken a relatively minor fact and given it far too much emphasis in the grand scheme of things.

While plants do spend energy converting NO3 to a more usable form having no water circulation around them is going to block other nutrients like CO2, Ca/Mg/etc from reaching the leaves. If you look at the hierarchy of what plants need most CO2 is wayyy ahead of NO3 in terms of nutrient demands, so if anything you'd be hurting your plants without circulation. Add on top of that poor oxygen circulation which prevents proper aeration of the soil and root systems and you have an anaerobic stinking mess more often than a nice soil planted tank.

Furthermore, there is plenty of ammonium and ammonia right in the soil from the decomposition process that goes on when adequate O2 is provided to the soil bacteria.

In addition, most filters don't really provide enough space for a huge amount of bio-filtration anyway, so they are really just circulating the water preventing it from becoming stagnant. Most of the time there is more surface area and therefore more nitrifying bacteria in the tank itself rather than in the filter only. Removing the filter is only going to remove a small portion of the nitrifying bacteria that has access to the ammonia in the tank, except when you remove that population by not having a filter you also get the above mentioned problems.

So I'd have to say it is _always _a good idea to have mechanical filtration and good water circulation.


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## qwe123 (Jun 15, 2011)

I don't think anyone was arguing against water circulation. The sole concern was against nitrification/biological filtration.


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## SBS (Feb 26, 2013)

Yes, I think the concern was whether bio-media filtration in NPT tanks has bad/counteractive effect.
It seems that there's a section in Diana Walstad's book mentioning about biomedia being counteractive in an NPT tank and people getting confused whether filtration is ok or not. Obviously the book doesn't put much emphasis on circulation either. 

I opened the thread for those that think biomedia is detrimental in a planted NPT tank to help them come to their own conclusions and not being afraid of experimenting one way or the other to improve the condition of their aquariums.


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## Zapins (Jul 28, 2004)

I have not read Diana's book, but I am sure the info in there is correct.

If she did not emphasize that you ideally should not have _any _bio-filtration then I think it is safe to assume the difference isn't huge between having filtration and not having bio-filtration.


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## Skizhx (Oct 12, 2010)

The only real problem with filtration is when it disturbs the surface of the water, or collects waste that would otherwise be decomposing into the substrate. Even this wont necessarily prevent a tank from being stable on its own.

By the same reasons for saying that biofiltration is bad for an aquarium, you could also say that driftwood and rocks, are bad. The water's probably bad, too, since there's likely to be micro-organisms in it that compete against plants for nutrients, too.

They've adapted to coexist with each other. The resources aren't usually that limited, and neither one is a strong enough competitor to have a significant impact on the success of the other.


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## qwe123 (Jun 15, 2011)

I didn't think this thread was created for people to argue theoretically but to show actual tanks that demonstrate one way or the other...


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## SBS (Feb 26, 2013)

> If she did not emphasize that you ideally should not have any bio-filtration then I think it is safe to assume the difference isn't huge between having filtration and not having bio-filtration.


She actually emphasizes on biofiltration being counteractive. She does not recommend the usage of biofiltration, especially HOB filters that have access to aerial oxygen, thus providing a very good home for nitrifiers who love oxygen. But then HOB filters are great oxygenators of water too?...

She mentions that water pumps/powerheads can be used on large aquariums but not needed in small ones. She's totally against surface agitation too(in the book) This to some people sounds that they don't need either a filter or even circulation in the tanks.
The problem is that this contradicts with everything else she explains in the book, such as oxygenation and its great importance to decomposition of accumulated organics and production of CO2.CO2 needs oxygen to be produced by various processes including via methane oxydiation. Hydrogen Sulfide accumulation prevention and destruction needs oxygen, etc..all explained in the book....Substrate becoming anaerobic being the biggest threat and should be prevented as it will affect plants and fish according to her.

And as most know oxygen is the biggest limitation in fish tanks. It's hardly dissovable in water, less so than CO2 is in water. And without it or shortage of it there will be no CO2/lack of CO2(in non-injected tanks), plants will suffer(melting roots for example)the substrate will go anaerobic, and then the entire tank balance will collapse.

However, by eliminating surface movement(oxygenation in still water via equilibrium takes years), reduces the constant supply of oxygen if plants aren't capable of supporting themselves and the bioload with it(plants consume oxygen too), lack of proper circulation even more so by not pushing that oxygenated water down to the substrate and in a scenario where oxygen becomes defficient in a tank which is a likely scenario, everything can go bad.
And as you say, you can't eliminate nitrifiers by simply not having bio media in the filters and Diana explains that in the book too by giving examples how plant roots become home to nitrifiers and other good bacteria by simply providing oxygen into the substrate and that's essential. She explains how heterotrophs that decompose organics(release CO2) also release ammonia, which in turn gets used up by the nitrifiers, which in turn are protected by denitrifiers which consume the produced acids nitrifiers are sensitive to. This symbiosis she calls a "biofilm" explaining how all of these nitrifiers,denitrifiers, heterotrophs and other important bacteria exist in filter media and the soil substrate. Then she explains the importance of biofilms , one "most important" according to her being decomposition of organics(which we know the fish and plants produce constantly) And I can go on from the book.....but there's some contradicting info between her advises and explanations of how a healthy tank works....

So everyone can go on and make up their own conclusions but it seems some are reading just the "readable" part of the book and skipping on the chemistry formulas. And I am sure Diana recently advised against not having any surface movement and circulation as she now believes the importance of having that extra bit of oxygen.
As for biofiltration, I just don't see how not having biomedia will be negative to anything as nitrification is part of the substrate function anyway and having more surfaces for that just increases the available surfaces with that difference possibly that the important oxygen in the substrate is provided mostly by plants and oxygen in filters is provided by water circulation and a degree of surface movement for the most part, additionally preventing rapid organics accumulation which the plants and substrate may not be capable of supporting depending on bioload. Increasing oxygenation along with your filtration and proper circulation certainly goes along with the scientific information she provides in her book. And I can only say according to my experiment, having biofiltration has no negative but positive effect, at least on my tank.

Her other points of biofiltration is that "if" it outcometes the plants for ammonia, nitrAte accumulation can occur due to plants still prefering the constantly produced ammonia because nitrAte is harder for plants to consume(not in my case though) Also, nitrification and acidification goes along with each other and water can become acidic faster(not in my case but I have hard water) This can actually be a problem in soft water tanks and she emphasizes on the importance of calcium/magnesium and using the correct soil depending on the type of water one uses(some soils like John Innes contain lime keeping the water harder and preventing acidification but they are making the water quite hard at the same time so that's a negative if one keeps specific fish species not appreciating that). But that's a different topic regardless of whether biofilters or not are used, as nitrification in the substrate occurs anyway so I just don't follow her recommendations and use filters but I follow her logic of importance of oxygenation all around the tank and the importance of "biofilms"


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## Skizhx (Oct 12, 2010)

Diana does make her case against bio-filtration. She also admits that whatever impact the bio-filter may have may be dwarfed by having a tank that otherwise promotes good growth.

Oxygen levels will be high enough to support fish, even in stagnant water, as long as there is a plant-mass producing oxygen. It's impressive how much oxygen plants produce.

I've never specifically come across rates of atmospheric oxygen diffusion into oxygen-depleted water to reach equilibrium, so I can't comment on it taking years, but I would be interested in seeing a reference on this, for my own knowledge.

In the case of substrate being "anaerobic", we're not actually talking about "absence of oxygen", so the term is a bit misleading.

With all that out of the way, despite Diana's book being one of the most scientific books out there on the subject of planted aquariums, a fair amount of it still draws from personal experience with only theory to back it up. In other words, she's proposing some of her own theories, which simply means that there's room to test those theories.

I'm not saying you don't have a point (and you do), but to repeat what I've already said "The resources aren't usually that limited, and neither one is a strong enough competitor to have a significant impact on the success of the other.". If you wish to discuss anything that I've presented directly, I would rather it be in PM than on the open forums.

And to stay closer to the thread topic. My stagnant tank with no equipment, except lights:









The plants arrive for my special project tank in a week


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## SBS (Feb 26, 2013)

> I've never specifically come across rates of atmospheric oxygen diffusion into oxygen-depleted water to reach equilibrium, so I can't comment on it taking years, but I would be interested in seeing a reference on this, for my own knowledge.


Here is one:



> Oxygen is absorbed in water by direct diffusion and by surface-water agitation. Solubility of oxygen in water is so small and by diffusion process alone in still water, it was culculated that it would take 6 years for oxygen to diffuse from surface to a depth of 6 meters in quiet water.


Source: http://www.fao.org/docrep/field/003/ac183e/ac183e04.htm


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## SBS (Feb 26, 2013)

> Oxygen levels will be high enough to support fish, even in stagnant water, as long as there is a plant-mass producing oxygen. It's impressive how much oxygen plants produce.


They'll produce oxygen as long as there's enough CO2 and light. Availability of CO2 in an NPT tank depends on availability of oxygen.


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## turtlepower129 (May 21, 2013)

error


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## herb_remington (Jun 21, 2013)

Added a Marineland magnum 350 pro with bio-wheels to my 125g last week and put some prefilter media in it and my other magnum 350 w/o bio-wheels.

I looks like my algae problems immediately disappeared. I could be the added filtration or the 5 ammano shrimp in the tank that i never see, but the change was abrupt. All the algae on my leafy plants is gone and the GHA is only on my moss. Whereas it used to be all over my driftwood. I also have pond snails, but they where unable to keep up with the algae.


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