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Discussion Starter #1
I was wondering just how important a biological filter is in a modern panted tank?
I mean, if you carry out a 50% water change every week, keep a minimal amount of live creatures & have a large amount of healthy flourishing plants, do you actually need a dedicated biological filter unit?
I am not talking about water flow here or mechanical filtration or even biological activity within the tank just the importance of a dedicated pump fed biological filter?
 

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I'm gonna try to see if i can predict where you're going with this... you want to just put a powerhead in your tank for flow, but leave out the filter. I think that it's really doable if you go with a small amount of fauna and a fair amount of flora.
 

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According to Diana Walstad - "In my planted tanks I have been surprised at how little biological filtration is actually required."..... "Althought filtration is essential in tanks without plants, it is much less important in planted tanks, especially those with a soil underlayer."

Of course, I'm not sure how much her comments are specific to the type of low tech planted tanks that she maintains. My understanding, is that she does not recommend giving up on biological filtration altogether, but only that it is much less important than most people think, and that we can get by with much less filtration.

http://thegab.org/Plants/setting-up-a-walstad-natural-planted-tank.html
 

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I would say no. Essentially, a filter is a sump, that has biological media in it in which the water passes over. I do filter though, often over filter, cause hey, it never hurts.
If you had a tank with a very high and HEALTHY plant load, with a lower bioload, I would say that the water changes are sufficient enough, given you know what you're doing and are experienced enough to know water parameters and stability.

**Do note though that I am not telling you to not filter**
 

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Bacteria lives all over the place in a mature closed system and will "filter" an aquarium without the need of any artificial "filter media", really. Well, the truth is that we have enought "filter media" (rocks, substrate, drift wood and even glass walls).
That´s a fact. If one substiture the artificial filter media (read: ceramic rings or similar) for a little more soil, that probably will do it. And again, maybe don´t even need to do so, depending of the system.

Basically we can say that the artificial filter media will help to keep those excesses of bioload that we want to keep (speaking mainly of the fishes). That is because of the animal/ space relationship.

I guess water changes are essencial to keep ANY TYPE of aquarium running at it´s best filtration stage. No doubt!

Just my $.02.
 

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Yep

I actually have a 5g tank with one fire eel and one snail. The powerhead is pretty much just blowing a current, i.e. not working correctly...and all I do is change the water regularly. The problem that people run into when they don't cycle or don't have enough surface area for bacteria to grow on is that all their fish die because they either overstock, overfeed, or don't do water changes. Plus, the fact that plants detoxify the water makes it even more pointless to buy all sorts of fancy filters.
 

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This is simple: The added biofilter in a well established planted tank is just an insurance in case something happens. You don't need it.

But a planted tank is a very dynamic system. It can run fine for months on end and then one sunny day decide that it wants to do something else. That's when the added biofilter steps in.

Some time ago I had a tank whose canister broke. It was a well established tank. For 3 weeks the tank had only one powerhead. What I saw was pretty intresting - no issues whatsoever. Just the plants grew just a little bit faster. I guess the Ammonia that was normally consumed by the canister biofilter was now available to the plants. And plants do prefer Ammonia as we all know.

So, bottom line is - yes you can run a planted tank without a biofilter. The bacteria living on the plant leaves, on the gravel, on the decorations and so on is enough. But watch out for the "mood swings" of the tank.

--Nikolay
 

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This is simple: The added biofilter in a well established planted tank is just an insurance in case something happens. You don't need it.

But a planted tank is a very dynamic system. It can run fine for months on end and then one sunny day decide that it wants to do something else. That's when the added biofilter steps in.

Some time ago I had a tank whose canister broke. It was a well established tank. For 3 weeks the tank had only one powerhead. What I saw was pretty intresting - no issues whatsoever. Just the plants grew just a little bit faster. I guess the Ammonia that was normally consumed by the canister biofilter was now available to the plants. And plants do prefer Ammonia as we all know.

So, bottom line is - yes you can run a planted tank without a biofilter. The bacteria living on the plant leaves, on the gravel, on the decorations and so on is enough. But watch out for the "mood swings" of the tank.

--Nikolay
+1,

Never hurts, and I like clear clean water that mechanical filtration provides.

regards,
Tom Barr
 

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Sorry for going a little sidetrack - but is it true that bioloigical filter will not work if PH is lower than 5.5? I'm pretty sure I've read this somewhere.
 

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Discussion Starter #11
Hmm - well I do in fact have quite a large filter but the sump was used in a marine system that I simply converted.
I am now considering redesigning the sump base by removing the sintered glass & perforated gravel support.
I think a simple slopping false base & a three part sponge biological filter will be more than adequate?


 

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I was thinking the same thing this weekend so I turned off the canister filter on my 75g tank. I have a Koralia 4 that provides plenty of water flow in the tank. I have been checking ammonia levels each morning and evening, and so far all are at zero.

My fish load is pretty low. I have a pleco (about 3in), red tail shark (1.5in), 5 balas (3-5in), and 8 tiger barbs (1-1.5in). And I have a few pots of Green Temple Narrow that seems to soak up nitrates pretty fast.

Negative is that I have a lot of driftwood in the aquarium that is turning the water yellowish. Charcoal in the canister would take care of this. The benefit for me is that I live in a sixth floor apt and I have always been a little scared of some catastrophe with the canister filter.
 

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+1,

Never hurts, and I like clear clean water that mechanical filtration provides.

regards,
Tom Barr
I think that only if you place a bag of activated carbon in the canister for the "mechanical filtration" that would be truth.
Other than that would be the use of ozone.
 

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Sorry for going a little sidetrack - but is it true that bioloigical filter will not work if PH is lower than 5.5? I'm pretty sure I've read this somewhere.
Nitrifying bacteria shut down, but plants can still photosynthesize just fine... so it depends on what you're relying on for your biological filter.

Personally, I always overfilter my tanks. Plenty of mechanical, biological, and chemical filtration. Less work for me, more leeway for getting busy with other stuff that pops up.
 

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I think that only if you place a bag of activated carbon in the canister for the "mechanical filtration" that would be truth.
Other than that would be the use of ozone.
I don't follow you... activated carbon is generally considered chemical filtration...?
 

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Hmm - well I do in fact have quite a large filter but the sump was used in a marine system that I simply converted.
I am now considering redesigning the sump base by removing the sintered glass & perforated gravel support.
I think a simple slopping false base & a three part sponge biological filter will be more than adequate?


I´m in a process of designing my sump.
Would you please tell me about your experiences with CO2 loss, if so.
Is your sump closed (lids). I can see a hole on the side...

Thanks
 

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...
Negative is that I have a lot of driftwood in the aquarium that is turning the water yellowish. Charcoal in the canister would take care of this.
...
You can place the carbon in the display behind the plants in a fine bag, but weekly water changes would be enough to remove the tint, I believe. At the beggining you could do twice a week water changes.
 

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Discussion Starter #18
My sump is not covered & the main display has a 6x an hour flow though.
I have to feed 3bpm for fast growth but the tank sits quite happily at 1bpm with very little algae if I keep the lighting down to 2wpg.
At one stage the tank used a 250w metal halide & I found I couldn't get enough Co2 in the tank!
There are benefits though - no visible equipment in the display tank & you can add ferts in the overflow for good mixing. Evaporation is compensated for & obviously you have more water in the system but weather that is good or not depends on your views & budget for ferts!
The tank has an overflow in the center of one end of the tank & the return water is divided into two outlets at the opposite end of the tank.
So in theory the "C02 rich return water" is directed to flow right though the tank but I guess by the time the circulated water reaches the sump it has very little Co2 content?
I am not a planted tank expert but as this system was running as a marine set up (30x flow though) I just changed a few thing around!
 

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I was thinking the same thing this weekend so I turned off the canister filter on my 75g tank. I have a Koralia 4 that provides plenty of water flow in the tank. I have been checking ammonia levels each morning and evening, and so far all are at zero.
Last night I opened the lid of my tank and it smelled a little funky, sort of like rotting plant matter. Everything looks fine. But I turned the canister filter back on.
 

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Last night I opened the lid of my tank and it smelled a little funky, sort of like rotting plant matter. Everything looks fine. But I turned the canister filter back on.

It probably needs water change, not necessarily the filter back on.
I would live it alone for 2 more days or do apartial water change.
Maybe it will go away, depending on how many fishes / food you get running.
 
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