# Filterless- why do you have a filter?



## MiamiAG (Jan 13, 2004)

We all know that plants prefer ammonium over nitrate. We also know that our very efficient biological filters quickly reduce ammonium to nitrate via bacterial filtration.

The question is, why do we put filters on our tanks as they clearly compete with our plants? Have you thought about that? Why aren't we all filterless?

Are you currently running without a filter?? Tell us about it! When and why did you make the switch? How's it going?


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## fishmaster#1 (Apr 10, 2005)

I use filters to keep water moving. I find plants don't do as well in still water UNLESS they are growing semi-emerse. Just my exp. I never run carbon or anything other then floss + sponge. 
Snails also grow bigger faster in moving water. If one dies the rot does not kill stuff as easy. It gets spread around.


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## trenac (Jul 16, 2004)

I use filters...I guess it just and old habit from my plant-less days. 

However without a filter I feel that the tank would get too dirty, I like the fact that a filter removes debris from the water and keeps the water circulating. 

I have thought about getting Diane Walstads book and one day trying a all natural filterless tank.


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## Piscesgirl (Feb 25, 2004)

Filters are peace of mind, to me, plus as said before -- water movement. However, that said, I have one filterless tank that is my most successful at this time. I have four Killifish in a 20 gallon long with only an airstone. And, DIY Co2 that is actually so high, I've had to unplug it the last several nights with a new batch (was running at least 45 ppm with Hagen ladder AND airstone). I do overfeed, however, which results in too many planaria (it seems the planaria are outcompeting the snails, unfortunately)


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## Sir_BlackhOle (Jan 25, 2004)

Most of my tanks run filters. Mainly to keep the o2 level up and remove particles from the water column. Without them the tank bottom starts to look ugly. I do have some killie tanks, fry tanks, and betta tanks that I do not use filters on, but I do frequent water changes with these tanks.


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## Bert H (Mar 2, 2004)

Never having had any experience with filterless, I can't imagine the water would be as crystal clear without them, and I like that clarity. Plus, for me, it's the simplest way to get the co2 in there, either via external plumbed reactor or by using the filter as reactor itself.


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## plantbrain (Jan 23, 2004)

Art_Giacosa said:


> We all know that plants prefer ammonium over nitrate.


I don't know that. Both observations and theory seem to contradict that statement.

You can simply pick up DW's book and see the rates when the NH4 is less than 0.5ppm NH4, are less than NO3 uptake rates.
At higher levels of NH4, say over 0.5ppm, the NH4 is preferred.

Unless you have such high NH4 levels, the experiment she cites(Ozimek who uses a submersed aquatic weed which would apply to us here) does not support her contention, rather, every planted tank I've ever seen has a very low NH4+, general immeasureable.

Looking at Ozimek, the rate of uptake at 0.1ppm is zero NH4/unit time.
But NO3 uptake is steady.

Concentration drives uptake in enzymes, the higher the concentration, the faster the uptake.

While it is true at the cholorplast level, that the NH4 is assimilated into glutamine first and NO3 needs reduced in two more additional steps in order to be assimilated, that is not all of the story.

Plant cells can store far more NO3 and have a reserve in the tonoplast.

If the tank is doing well, less light, slightly N limited/lean N etc, you'll have more success with filterless tanks. They are not as robust with regards to algae and GW blooms. You'll learn that in due time. This is a rather old debate. I'd rather have a few NH4+ oxidized to NO3 by bacteria as a back up, than algae.

It did not influence the growth rates near as I can tell. Increasing the NO3 did on the other hand. I also have a lot of dosing experience with NH4 specifically in the water column. I have not found it to improve things for our applications. Maybe I need to add 1-2ppm a day?

That's fine if you have no fish and UV and don't mind algae.......
Or another option that worked: daily 80% water changes.

A number of aquarist here in the bay tried using NH4 in small amounts to amplify growth. It's not what you think in practice. All abandonded it rather quickly.

The filterless idea's notion is based on the NH4= NO3 issue, but increasing current, CO2 offgassing etc and other factors come into play.

Isolate the issue you have a question about to see which issue is really significant.

NH4=NO3 issues are not as significant unless you add NO3 on equal terms with NH4.

I'd look for other reasons.

Regards, 
Tom Barr

www.BarrReport.com


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## TWood (Dec 9, 2004)

I ran my 90 gallon filterless for years and it did fine. There's an overflow into an in-tank sump with a submersible pump for the return flow, but no actual filtering. I recently added a DIY UGF made of perforated PVC so I'm now using the plain gravel (1-3mm in size) substrate as a mechanical filter. I like the better water clarity. 

TW


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## plantbrain (Jan 23, 2004)

A UG or a RFUG is a huge biofilter.

Regards, 
Tom Barr


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## fishfry (Apr 15, 2004)

I run a 26 gallon tank without a filter and the plants grow fine, I also don't fertilize it and the plants grow like crazy still. I think there are over 30 species in that tank too. The tank is a mess and was dubbed a "swamp" by another hobbyist. My real tank I do have a filter and fertilize.


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## TWood (Dec 9, 2004)

plantbrain said:


> A UG or a RFUG is a huge biofilter.


Understood, but if there is very little NH4 in the tank, such as with a light fish load and/or heavy planting, what is being biofiltered?

TW


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## Anafranil (Mar 15, 2005)

Regarding what has been said from Plantbrain above,I came whith this question:Can the algae in my heavily planted tank be a result of not having any bacterial cultures in the filter,so NH4 stays long enough in the tank to cause algae before is absorbed by plants?


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## Sir_BlackhOle (Jan 25, 2004)

Even without a filter I believe beneficial bacteria cover just about every surface in the tank, including gravel and plants. If this is truly the case then even without a filter there should be enough benebact to take care of the NH4 before you have an algae outbreak.


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## plantbrain (Jan 23, 2004)

TWood said:


> Understood, but if there is very little NH4 in the tank, such as with a light fish load and/or heavy planting, what is being biofiltered?
> 
> TW


Not much

I've kept a number of tanks without fish/snails etc.
I've also over loaded tanks on purpose.

Regards, 
Tom Barr


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## plantbrain (Jan 23, 2004)

Anafranil said:


> Regarding what has been said from Plantbrain above,I came whith this question:Can the algae in my heavily planted tank be a result of not having any bacterial cultures in the filter,so NH4 stays long enough in the tank to cause algae before is absorbed by plants?


Yes, see all the new tank start ups where the bacteria are not established. GW is a very common occurance. If you add the bacteria(mulm from an established tank) then you don't have this problem.

If you add NH4 to the same tank, you'll also get GW.

Regards, 
Tom Barr


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## plantbrain (Jan 23, 2004)

Sir_BlackhOle said:


> Even without a filter I believe beneficial bacteria cover just about every surface in the tank, including gravel and plants. If this is truly the case then even without a filter there should be enough benebact to take care of the NH4 before you have an algae outbreak.


Unless the conditions for the plants go sour for any reason. 
Which if you have higher light, can occur rather easily.
It'll work, but over time due to our own issues, GW and other algae have a much esier time establishing themselves without biomedia.

Anyway, you need some circulation, so a filter does a good job there and makes for a good back up for errors in our dosing, and plant care. A single tube in/out vs a powerhead in the tank provides less space requirements also.

Try inducing GW with and without biomedia.
See if you can keep the GW away once killed with a UV afterwards without and with biomedia.

That will tell you a thing or two.

Yes, you can do it without algae, but what do you gain vs what do you lose?
I'd rather have removal of muck in my tank, less chance of algae than a small insignificant extra NH4 contribution.

Since the bacteria is all over the surfaces/gravel as SBH says, would that not be the same as biofilter media? So why would the filter removal help in that case?

May as well have a back up.

But.........the filter bacteria colonize and perform better in areas of high water flow. So a filter is good for that. The bacteria need a fair amount of O2 to do well. This is the *indirect effect of high O2 in a planted tank since O2 drives the bacteria more efficently/faster to convert NH4(the reduced form of N) to NO2/NO3.

Regards, 
Tom Barr*


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## Phil Edwards (Jan 22, 2004)

Art_Giacosa said:


> The question is, why do we put filters on our tanks as they clearly compete with our plants? Have you thought about that? Why aren't we all filterless?
> 
> Are you currently running without a filter?? Tell us about it! When and why did you make the switch? How's it going?


I like filters because they serve multiple useful purposes, keeping the water column clearer, circulation, and diffusion of CO2. I'll always use a filter on a high-tech "industrial farm" tank where I'm pushing growth to artificially high levels. Filters are useful in tanks like this to remove things that would otherwise uncontrollably add nutrients to the water column. In cases like this filters become another element of control over the system.

Other than those high-tech tanks I prefer to go filterless. I like to think of these tanks as my "organic farms" where things can grow naturally. A soil-based substrate and no filter accomplishes that with aplomb. In the times where I've had a lot of tanks going at once the majority are of this type simply for ease of keeping. Since most of my favorite plants do really well in this type of system I'm somewhat partial to it.

Right now I've got a 29g native species biotope that's growing really well this way and is easily my favorite current tank. The plants are all growing, the fish are doing well and all I have to do is top it off. Yes, there's some algae, but there's a lot of algae in the area I collected everything. In my mind it's just as important an element of the tank as the plants and fish. As long as it's not overwhelming that is. 

Regards,
Phil


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## plantbrain (Jan 23, 2004)

I have done a few tanks without filters lately. I recently added them, they are small tanks with a lot of light but I can adjust the light over a wide range.

The main reason was simpoly the tanks were too small to have a filter but I add some of those Azoo palm filters and adjusted them to reduced flows.

I had plenty of emergent growth, the tanks did well. 
I think folks need to slow down their light and let the density build up good.

It's tough to start a tank without one.
But removing them later after the weeds have grown in, is certainly possible. But then there is no NH4............due to biomass, and surface bacteria, less light also..........

You add CO2, lots of light and no biomedia........well, we'll see...........
Maybe not today.........but sometime.........

I think the gain is not from the NH4/NO3 issue...........it's more of simplcity.
Small ponds, pools etc, emergent growth is a wise move on these filterless tanks.

Regards, 
Tom Barr


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## Plattykins (Apr 3, 2005)

I attempted to convert my tanks to filterless recently, but I believe I need more plants to balance the tank in order to be successful. I ended up putting the sponges back in the filter boxes and am still running filters now. I would like to try it again sometime though and make the switch over a longer period of time as well. The first attempt occurred over just a few days, removing one of the two sponges on each of the tanks and then the second after a couple of days. In the end, I put them back one at a time, because I was observing ammonia spikes within a couple more days, and performed small water changes until the tanks were back to normal. It was interesting to try it though.

um... to answer the question, I always used a filter because it either came with the tank or because I was "supposed to". I can see though, since I have learned more over the years, that the filter is not necessary, depending on the tank, how many fish/plants are in the tank, etc. But I also know that having one is what works best for my tanks, by providing the necessary bacteria to handle the load.


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## plantbrain (Jan 23, 2004)

Art, 
Bacteria and plants do not "compete", they are not in the same niche.
They may use some of the same resources but the scale differences makes they totally different.

Same deal with gasshoppers and Elephants.
Hardly competitors......

Regards, 
Tom Barr

www.BarrReport.com


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## MiamiAG (Jan 13, 2004)

Tom,

Thanks. I do realize that plants and bacteria don't compete in the classic sense. I would hardly compare them as such.

The question was that if both make use of ammonium why would we try to cultivate a large, efficient bacterial culture in a filter?


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## plantbrain (Jan 23, 2004)

I would think the plants are effective at dealing with NH4 when healthly..........

but what happens when they are not healthy?????????

Algae........

Why???????????

NH4............

Less NH4 is taken up.

The large filter is uneeded, a moderate filter is fine for most cases. A wet/dry and a large biomedia section is nice for high fish loading.

The bacteria will level off to whatever NH4 resources available to them population wise.

Give that, it is preferable to have filter bacteria over NH4.

Over time and with experience, folks can see a definite pattern with algae and filters/biomedia.....

We can kill the bacteria and have at least 2-3 weeks till it start to work and NO2 is easy to measure.

So we can substract the NH4-NO2 to get what was used by the bacteria or not over the time peroid. Then add plants to another treatment to see what the plants used up also.

Many hobbyist are unwilling to do this type of thing, but it does answer the question fairly well and does not take lab to do it.
Small tanks work as well as large ones.

I am going to address a number of nitrogen questions and do some more rigorous testing on Nitrogen and denitrification in the coming months. I can bring the lab equipment home to do things and measure very small amounts, in the 10ppb range for NH4, NO3, NO2.

No hobbyist have that ability.
This will give extremely accurate readings.

Regards, 
Tom Barr


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## Sir_BlackhOle (Jan 25, 2004)

Im looking forward to hearing more about that.


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## plantbrain (Jan 23, 2004)

Myself as well, some of these questions have been nagging me for a long time.

I also have some test to run on a marine planted tank and need the accurate test for that project.

These test only need a week or two, nothing too long.

Regards, 
Tom Barr


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