Why filter?

[Soilwork]

A question for those that don’t want to fertilise their plants. Why use a filter?

I can understand the reason behind encouraging massive microbial nitrification in a water treatment facility but in a planted tank that doesn’t use fertiliser you filter is removing ammonia and microscopic particulate food for your critters. Let the plants do the work and feed heavily. I don’t agree with all of Diana Walstads principals but she was right when she said ‘you’re not feeding the fish, you’re feeding the plants’

If you allow the mulm to build up in the substrate gives a better medium for your plants to grow in over time and doesn’t encouraging high turnover increase oxygen demand? I know this can easily be overcome but I prefer slower flow, no mechanical filtration and overfeeding. There is definitely a better response in these kind of natural aquariums in my experience.

Cheers CJ

 

[Edvet]

There are a few examples of low tech tanks, amply planted, laden with critters and a few fish, that work very well.
First one i read about: https://www.tuncalik.com/2009/09/biotope-in-my-study/
Wellknown here on Ukaps:https://www.ukaps.org/forum/threads/toms-bucket-o-mud-the-end.14521/

You might need a way to break up surface scum which would hinder gas/surface interaction

 

[dw1305]

Hi all,

If you allow the mulm to build up in the substrate gives a better medium for your plants to grow in over time and doesn’t encouraging high turnover increase oxygen demand? I know this can easily be overcome but I prefer slower flow, no mechanical filtration and overfeeding. There is definitely a better response in these kind of natural aquariums in my experience.

You probably don't need the microbial filtration offered by the filter. "Filtration using plants" is always really filtration using "plants and microbes", and I think you will end up with a similar amount of microbial filtration when you have plants, whether they are in the filter or in the rhizosphere.

I have had this conversation with @Bart Hazes somewhere (I can't find exactly it on <"UKAPS">, but it might have been a PM, or it may be on Apistogramma forums or his blog etc).

......your filter is removing ammonia and microscopic particulate food for your critters..........and doesn’t encouraging high turnover increase oxygen demand?

It may increase oxygen demand, but I'd look at the question from the other direction.

My worry for the livestock would always be sub-optimal oxygen levels. If you have a heavy planting you may end up with low oxygen/high CO2 levels towards the end of the night.

You can circumvent this by increasing the gas exchange surface area (adding flow) and/or by reducing the bioload. If you have a filter, with aerobic filter media, that gives you both flow and extra nitrification capacity, and that can never be a bad thing.

cheers Darrel.

 

[Kalum]

For me the decider is if you come at it from the fish keeper or plant keeper mindset

As as fish keeper the question would be 'why wouldn't you use a filter', giving them the best environment possible should be priority and even fish that are traditionally from mud pools and the like still deserve the best conditions we can give them in the glass boxes we put them in, it's like saying someone brought up in the smog of London wouldn't benefit from cleaner countryside air

Plant keeper side of things, why not

 

[Soilwork]

There are a few examples of low tech tanks, amply planted, laden with critters and a few fish, that work very well.
First one i read about: https://www.tuncalik.com/2009/09/biotope-in-my-study/
Wellknown here on Ukaps:https://www.ukaps.org/forum/threads/toms-bucket-o-mud-the-end.14521/

You might need a way to break up surface scum which would hinder gas/surface interaction

Thanks

The scum could become a problem considering I don’t water change but I’ve heard bladder snails are great for surfing this?

 

[Soilwork]

Hi all, You probably don't need the microbial filtration offered by the filter. "Filtration using plants" is always really filtration using "plants and microbes", and I think you will end up with a similar amount of microbial filtration when you have plants, whether they are in the filter or in the rhizosphere.

I have had this conversation with @Bart Hazes somewhere (I can't find exactly it on <"UKAPS">, but it might have been a PM, or it may be on Apistogramma forums or his blog etc).It may increase oxygen demand, but I'd look at the question from the other direction.

My worry for the livestock would always be sub-optimal oxygen levels. If you have a heavy planting you may end up with low oxygen/high CO2 levels towards the end of the night.

You can circumvent this by increasing the gas exchange surface area (adding flow) and/or by reducing the bioload. If you have a filter, with aerobic filter media, that gives you both flow and extra nitrification capacity, and that can never be a bad thing.

cheers Darrel.

Hi Darrel,

My thoughts are that even though you have microbes the lower turnover and lack of mechanical sponge benefits the plants by allowing ammonia uptake. Their increased growth enables higher oxygen levels in the water. The demand for oxygen simply isn’t as high in this system. Food doesn’t get drawn in to the filter to rot away consuming oxygen. Whats left on the bottom is quickly eaten.

I understand what you’re saying but I don’t think the low oxygen at night would be an issue in this kind of tank.

 

[Soilwork]

Here is an example of such a tank only this one doesn’t have a pump
.
No pump, no filter, no heater, no fertiliser, no water changes, just sand, lighting and fish food.

 

[Soilwork]

For me the decider is if you come at it from the fish keeper or plant keeper mindset

As as fish keeper the question would be 'why wouldn't you use a filter', giving them the best environment possible should be priority and even fish that are traditionally from mud pools and the like still deserve the best conditions we can give them in the glass boxes we put them in, it's like saying someone brought up in the smog of London wouldn't benefit from cleaner countryside air

Plant keeper side of things, why not

My fish do better in this system than any other i have tried.

 

[Edvet]

Are there a buttload of Daphnia i see?

 

[Soilwork]

Are there a buttload of Daphnia i see?

Yes despite there being two sparking gourami in there somewhere.

 

[dw1305]

Hi all,
Right at the start of this reply, I'd like to say to @sciencefiction, you are right, it is the plants that make the difference, not the filter.

.......giving them the best environment possible should be priority and even fish that are traditionally from mud pools and the like still deserve the best conditions we can give them in the glass boxes we put them in, it's like saying someone brought up in the smog of London wouldn't benefit from cleaner countryside air

Same for me.

My thoughts are that even though you have microbes the lower turnover and lack of mechanical sponge benefits the plants by allowing ammonia uptake.

The plants will still uptake the ammonia, but I think my main point would be that you will have a similar amount of microbes, whether you have a filter or not.

Even if microbial numbers are of the same order of magnitude, you are likely to have a more diverse microbial assemblage in a planted tank, because the plants will create a greater variety of niches, mainly via the oxygen and carbohydrates leaking into the rhizosphere.

<"Maximal biodiversity usually occurs in patchy environments">, where you have low nutrients and zones of fluctuating resources (oxygen, nutrients etc.), and that seems also to apply to <"nitrification in aquariums">.

Their increased growth enables higher oxygen levels in the water.

I'm not sure, I think that all reasonably heavily planted tanks will be pretty near oxygen saturation point at the end of the photo-period. You can even get pearling (via the Cyanobacteria) at sewage treatment works if the sun is out. Have a look at <"A question.....">.

Food doesn’t get drawn in to the filter to rot away consuming oxygen.

I think we probably all agree on that. I've always been an advocate of not using your <"filter as a syphon">.

I understand what you’re saying but I don’t think the low oxygen at night would be an issue in this kind of tank.

That is the great unknown, <"it is going to depend on all sorts of factors">.

I actually look on dissolved oxygen as different from all other parameters, because it only needs a very short period of time where it is sub-optimal to kill all your fish. Everything else you get a bit of warning, or wriggle room, but with dissolved oxygen you don't.

My argument for keeping a large gas exchange surface is <"really "risk management"> or "belt and braces" one. You may not run much risk of having low dissolved oxygen levels, but if it does occur the consequences are as severe as possible, and having a filter removes a single point of failure.

My fish do better in this system than any other i have tried

Are there a buttload of Daphnia i see?

Yes despite there being two sparking gourami in there somewhere.

<"Anabantoid fish"> are the safest option in a tank without flow, because they have the ability to extract oxygen directly from the air via their labyrinth organ.

I've found that Daphnia do better in a tank with no flow as well.

cheers Darrel

 

[Joel S]

I recently set up a 60cm tank having had success with a very small filterless tank. On the 60cm I had a lot of initial melting that did not happen to the same extent with the smaller tank (there are other major variables like harder tap-water and different substrate and more slow-growers) but I was amazed to see the plants (and lethargic Otos and shrimp) perk up the moment I added a small amount of flow from a little internal filter.

I’m still interested to go filterless on this tank perhaps when the plants are more established, but new leaves only started to appear after I added this small amount of flow (of course it could just be down to the general settling of the tank, but the improvement was so fast...)

 

[roadmaster]

Dissolved Oxygen levels at night would be easy to measure with DO meter with/without flow from pumps or filters no?
I place much higher value on livestock than weeds ,and though plants might not be affected too adversely from no filtration or movement of water,I could maybe not be so confident regarding livestock.
Some species more needy that others with respect to O2 and comfort levels,

 

[dw1305]

Hi all,

Dissolved Oxygen levels at night would be easy to measure with DO meter with/without flow from pumps or filters no?
I place much higher value on livestock than weeds ,and though plants might not be affected too adversely from no filtration or movement of water,I could maybe not be so confident regarding livestock.....

Yes, it would be easy enough with a DO meter, unfortunately they are expensive bits of kit. We actually have some in the lab (for water testing in the field), but I still haven't actually left one logging in an aquarium.

We do have a thread that looks at this, but <"using pH as a proxy"> for oxygen/CO2 content. This is the thread <"Maxing CO2 in ....">.

Some species more needy that others with respect to O2 and comfort levels,

They definitely are, a fish from <"cooler, rapidly flowing water"> may be discomforted at oxygen levels that are absolutely fine for most fish.

cheers Darrel

 

[Soilwork]

Dissolved Oxygen levels at night would be easy to measure with DO meter with/without flow from pumps or filters no?
I place much higher value on livestock than weeds ,and though plants might not be affected too adversely from no filtration or movement of water,I could maybe not be so confident regarding livestock.
Some species more needy that others with respect to O2 and comfort levels,

I also place high value on my stock than weeds. This thread is supposed to discuss the relationship between all aspects of the tank and how they affect one another. I could easily argue that I care for my livestock so much so that I removed my co2 injection and stopped doing large weekly water changes or dosing fertiliser. But as we know, that would stir up another discussion. We all look at things differently.

This no flow tank has shrimp and Daphnia as well as the anabantoids. If we use the daphnia, canary and coal mine analogy as has been used once or twice before for determining water quality. BOD should also be included in this. The thriving daphnia should offer an interesting insight here.

 

[roadmaster]

I also place high value on my stock than weeds. This thread is supposed to discuss the relationship between all aspects of the tank and how they affect one another. I could easily argue that I care for my livestock so much so that I removed my co2 injection and stopped doing large weekly water changes or dosing fertiliser. But as we know, that would stir up another discussion. We all look at things differently.

This no flow tank has shrimp and Daphnia as well as the anabantoids. If we use the daphnia, canary and coal mine analogy as has been used once or twice before for determining water quality. BOD should also be included in this. The thriving daphnia should offer an interesting insight here.

My apologies. Threads title "Why Filter"was all I saw. My observations with respect to O2 levels that may or may not be what we might think was but one aspect rather than what you intended.
Believe there is always more O2 in moving water than stagnant water and have seen no detriment to weeds or fishes/inverts from such water movement so I feel it is win/win.

 

[Kalum]

I also place high value on my stock than weeds. This thread is supposed to discuss the relationship between all aspects of the tank and how they affect one another. I could easily argue that I care for my livestock so much so that I removed my co2 injection and stopped doing large weekly water changes or dosing fertiliser. But as we know, that would stir up another discussion. We all look at things differently.

This no flow tank has shrimp and Daphnia as well as the anabantoids. If we use the daphnia, canary and coal mine analogy as has been used once or twice before for determining water quality. BOD should also be included in this. The thriving daphnia should offer an interesting insight here.

I don't think you can ask the question of why filter without it being a discussion like it has been and like you say taking all aspects into account

You definitely have a point with co2 and to an extent ferts, but both of these are easily measurable by us that allow it to be kept within parameters to not adversely affect the livestock

I think if everyone took the no filter and no water change approach there would be carnage as not many would be able to execute it and keep it a good environment for livestock and plants alike

It's just something different and nobody is saying it can't be done, far from it, but a filter and water changes allow a safety net for me to ensure I'm doing what I can and one that I wouldn't be comfortable without

 

[Soilwork]

I don't think you can ask the question of why filter without it being a discussion like it has been and like you say taking all aspects into account

You definitely have a point with co2 and to an extent ferts, but both of these are easily measurable by us that allow it to be kept within parameters to not adversely affect the livestock

I think if everyone took the no filter and no water change approach there would be carnage as not many would be able to execute it and keep it a good environment for livestock and plants alike

It's just something different and nobody is saying it can't be done, far from it, but a filter and water changes allow a safety net for me to ensure I'm doing what I can and one that I wouldn't be comfortable without

Point taken, but I would argue that both ferts and co2 are not easily measurable at all, and you’re in the same boat in terms of trying to predict these levels as you would be trying to predict what levels of oxygen are suitable for fish.

The other thing I would argue is that I would trust aged aquarium water over anything that comes out of a tap. The daphnia can be used to support that feeling as I’m almost certain they would not survive in a tank as you describe.

We have gone slightly of piste from the original point but as I said it is all interrelated. I know Darrel mentioned that they use daphnia as a measure of water quality in some work streams. Low oxygen would be related to a high BOD which equates so poor water quality.

I don’t think the oxygen levels in this type of tank would fall as low as one would think.

 

[dw1305]

Hi all,

but I would argue that both ferts and co2 are not easily measurable at all.....The other thing I would argue is that I would trust aged aquarium water over anything that comes out of a tap.

I would agree with that. I'm not a CO2 user, I use a method which reduces fertiliser input and I've used rain-water since the 1970's.

I know Darrel mentioned that they use daphnia as a measure of water quality in some work streams

I do, mainly for the water butts. They are used in the bio-assay for water borne pollutants, but I think their tolerance of low of low oxygen levels would be higher than for a lot of fish. I'll find a reference with some figures.

I don’t think the oxygen levels in this type of tank would fall as low as one would think.

It is really back to <"Donald Rumsfeld"> and "best guess".

cheers Darrel

 

[Affinis]

Hi everyone,

Just to clarify things a little, the little filterless tank Soilwork posted above is one of my playthings.

It’s now just over a year old, just 8cm of sand, tap water, and light, no ferts or water changes.

I’ve had good success with this kind of aquaria over the years, but it’s really only suited to small rather shallow aquaria.
Larger setups generally require a small amount of circulation in my experience.

Going back to what Soilwork was saying about filterless tanks, I recently turned off the power filter on a very long established tank. (1995) Just replacing it with a very small powerhead for gentle circulation. What I’ve found really interesting, is that almost immediately the plants responded. It was almost like an on switch.

I’d be interested to hear any comments regarding this reaction.