# About undergravel filter???



## Glouglou (Feb 21, 2006)

Coming back to the party ( lot of liquid involve) after 20 years, i restart a new planted aqua with all the bells & whistle.

After a year or two in the process of pumping more and more co2 and dumping ferts in my tank, I want to back off and come back to a more natural approach. I will sneak in the EL natural from time to time to spy on the progress.
:spy:

Coming back from work, yesterday, I was thinking of what's my worst fear in the El natural way. Well, It's that substrate thing.
:fear:

• Dump Cow dung or whatever can feed plants in the tank.
• Put your onions in, lay back and enjoy.
:hippie:

All that look like almost like a fairy tale from Disney.
But like in all good fairy tale a bad and ugly shadow creep around our sunshine (making us realize that it is a sun out there) 


The onions suck-up all the cow dong that lay there, helpless, and they just shrivel and dye...
:icon_hang

*There my point: *( :bored: it's about time) all the natural puddle, river, ocean out there sip trough mud, sand, rock, clays in underground water deposit driving trough all nutrient from the water in the soil. Bingo, the soil is alive and forever replenish with nutrients.

In my old days:-({|= , this is what those undergravel filter was supposed to do, and in bonus our little plants don't have anymore cold feet by the movement of the hot water trough the soil.

Please, tell me... For exactly what crime the undergravel filter was ban for life! 
:help:​


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## sb483 (May 29, 2006)

Glouglou said:


> Coming back to the party ( *lot of liquid involve*) after 20 years,...


What sort of liquid, exactly?

*edit*: I think an answer to your "question" is, undergravel filters prevent the anaerobic conditions necessary for good plant growth - unless you have it for a couple of years and some mulm has developed in the filter, allowing some anaerobic regions for plant roots.

*edit2*: Also, fishfood has nutrients to keep the plants alive; instead of sucking nutrients in with a UG filter, you could just allow fishfood/mulm to accumulate on the bottom surface. Fishfood and less-frequent water changes/tank cleaning can keep the onions alive.


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## Glouglou (Feb 21, 2006)

*Ok*

The anaerobic purpose seem to be driven by the fact that anaerobique bacterias retransform ferric state iron in the ferrrous form.



> "The availability of some nutrients, particularly iron, in aquatic systems is complicated by the presence of mud (let's call it underwater soil) where anaerobic conditions (oxygen is absent) exist. In the process of cellular respiration, most bacteria use, as we do, oxygen (O2) as an electron acceptor. They reduce oxygen by adding electrons and hydrogen atoms to it to form water.
> (Reduction is the addition of electrons, and oxidation is the removal of electrons)
> 
> If oxygen is unavailable many species of bacteria can switch to other molecules as electron acceptors. They can reduce sulfate (SO4-2) to sulfide (S-),ferric iron (Fe+3)to ferrous iron (Fe+2) and nitrate (NO3-) to nitrite (NO2-) and then to nitrogen gas (N2), which is unavailable for use as a nutrient. This latter process is called denitrification, and is responsible for considerable losses, on a global scale, of nitrate from waterlogged soils. Under aerobic conditions (oxygen is present), iron compounds exist as ferric compounds, where iron is in the Fe+3 state. These compounds are all quite insoluble, and the iron is mostly unavailable to plants. Under anaerobic conditions, however, iron is reduced by bacteria to the Fe2+ (ferrous) state. Many ferrous compounds are soluble in water. The result is that iron is much more soluble in soil under water than it is in the water, assuming that oxygen is present in the water but not in the soil. Many aquatic plants become iron deficient if they do not have their roots in some anaerobic soil Manganese, another of the micronutrients, is similar to iron in that it also becomes more soluble under anaerobic conditions."


What I can see here it more Iron, manganese but on the counterpart they can transform sulfate in sulfide and drive out nitrate.

Well in my actual tank with only inert sand (with Seachem ferts spike) without undergravel filter I believe my soil condition are mostly aerobic and my plants never show iron deficiency.

And if I beleive the following Quote, iron in whatever form if introduced to the system, will finally be available to the plant.

The last Quote will help the anaerobique situation, but not discard in any case the aerobic situation...



> IRON COMPLEXING
> 
> Ferrous iron is soluble as a cation, ferric iron is not. However, ferric iron can form soluble complexes with many inorganic and organic ligands,
> 
> ...


and another:



> > Light breaks down ferric-edta (and other ferric chelates)
> > through a reaction
> > called photoreduction. Photoreduction is one of the
> > major pathways by which
> ...


A last Quote on the subject:


> Most plants have a fibrous root system or rhizomes that bind and stabilize the soil i.e. Anubias and Cryptocoryne. Aquatic plants with delicate less-developed root systems, like Elodea, tend to grow in quieter waters where erosion is less of a problem. The soils in which aquatic plants grow are predominantly anerobic. This reducing environment can become toxic due to accumulation of hydrogen sulfide and liberation of metals like copper. Internally, aquatic plants need oxygen for respiration, to prevent the accumulation of toxic metabolic end products like alcohol. Fortunately aquatic plants have an extensive oxygen transport mechanism called the "lacunal system." These gas-filled intercellular spaces (lacuna) provide a "flow-through" system that allows oxygen to diffuse from the leaves, down the stem and into the roots. Figure 1 is a closeup of the lacunal system in a plant root. There are two types of lacuna. Schizogenous lacunae are formed in the parts of the plant exposed to light. Oxygen pressure produced via photosynthesis, pushes open lacunae in the leaves and stems (Fig. 2). Lysigenous lacunae are formed when cells die and break down within the plant tissue. Lysignous lacunae are found in the roots and rhyzomes, parts of the plant that remain in darkness. Although still under investigation, some plant physiologists believe that diffusion of oxygen down to the root tissue helps the plant survive in an anerobic environment. It has been proven that oxygen, transported down from the leaves, is released through the roots. This produces an aerobic microclimate around the roots. While the anerobic soil contains nitrogen as ammonium, it is oxidized to nitrate, by nitrifying bacteria, in the oxygenated "rhizosphere" that surrounds the plant roots


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## Glouglou (Feb 21, 2006)

*Ok*

Double post
Sorry!


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## sb483 (May 29, 2006)

Well if you get good plant growth with aerobic substrates that's great! It sounds like you're adding fertilizers. If you also add a UG filter and plants still grow fine, then that's great news but this is starting to move away from a natural tank. If you replaced the sand at the bottom of your tanks with soil (potting, garden), then you wouldn't ever have to worry about iron - soil has a huge excess of iron, and while plant roots can get it, none of it is available to algae in the water.

You could even add CO2 to tanks with UG filters and regular fertilizer spikes, and with regular water changes (to remove the buildup of alleochemicals and anything the fertilizers might be leaching in excess into the water) it would do fine. The quotes you offered were geared towards showing that less natural methods like fertilizer sticks can also provide plants with iron, but why buy fertilizers (and a UG filter) when you could just let soil and fishfood and minimal water changes/tank cleaning do the same job?


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## Glouglou (Feb 21, 2006)

*Tanks sb483*

The tank I have now is more on the high tech. 3w/g, co2 pressurized, ferts.

Soon I will put together my dream tank, a big one, and I like to try a more natural way to do it, like I said before I really don't like, the more light, more co2, more ferts, more kind of way.

I probably go for something between the high tech and El natural ( I don't like to be restraint by convention)

My debate here is to decide what kind of substrate will be good.

The El Natural way will ask (if I understand) for an anaerobic bottom (mix of clay and peat as an example cover with dirt (maybe mix with vermiculite and sand to keep exchange of water and roots able to pass trough) around 4 inch deep cover with a more aerobic top (like different size sand, pebble).

If I'm right here, even high tech tank go with that kind of setup. (but it seem that some people try to go with a more aerobic soil?)

I like the idea, it's seem natural and smart to do that, the only dark area is the replenishment of that substrate, in nature it will naturally occurs by all the water column charge with nutrient sipping trough the soil. My idea here was a kind of Undergravel filter with a very small flow (that you can regulate) here can replace that movement and make the substrate easy to recharge with nutrient...

Maybe I should go back to my liquid


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## sb483 (May 29, 2006)

I'm not arguing with your method, I hope your tank turns out well (pls post some photos when it does ). You're saying a UG filter with a very small flow approximates nature, but how about mulm/organic material decomposing to form... soil? Isn't that an even closer approximation to nature (if it's an approximation at all)?

Since you're using some high-tech elements, I take back what I said - maybe you were right, an aerobic substrate might result in less problems in the future. If you ever decide to try out a *fully *low-tech, natural setup (as described completely in the Ecology of the Planted Aquarium book) one day, then maybe you should switch from sand and UGs to soil and less filtering.

*edit*: and fyi, plants can spread their roots just fine in potting soil or garden soil, there's no need to add sand to let the roots pass through


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## Glouglou (Feb 21, 2006)

*Thanks to be patient sb483*

In no way I'm trying to argue anything. I'm working with only one neuron, here, sorry
:wacko:

I try to be clear:

In this new setup I will use a nutritive soil, my only concern is to redo the full setup when the soil start to lose some property.

The UGF with a very small flow (or even no flow at all like in the Jaubert marine setup) is to bring back to the soil the nutriments it loose, I even wonder if with a small flow the lower portion of soil will stay somewhat anaerobic.

The goal here is to have a system that doesn't need to be reset from time to time.

Question: the bottom layer of choice (if I'm right in the El Natural system) seem to be clay?

My question is do you mix this with vermiculite or else to keep it to became a dense slab of clay??


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## sb483 (May 29, 2006)

The El Natural system that _I _know of (the one described in that book I quoted above, get it if you want, it's good) uses plain old garden soil or potting soil, covered with a layer of gravel. Nothing fancier than that. No mixing in anything. Just a layer of plain soil. If that's what you call "clay", then yes, the bottom is just "clay". Plant roots spread out fine in this soil, without any amendments.

You're right, after a while the plants suck up some of the nutrients in the soil underlayer. How to put those nutrients in? You're suggesting a UG filter to "suck them in" slowly. Maybe someone else suggests regular addition of fertilizer sticks. The method described in the book says "Feed your fish well, don't clean the tank bottom, and just sit back". Fishfood has all the necessary nutrients for the plants. There's a whole chapter on the chemical uniformity of organic matter that explains why fishfood is just as good as any fertilizer, or as good as injecting those nutrients into the soil with a UG or with a syringe. In fact, this chapter explains why fishfood is better, and less likely to cause algal outbreaks.

You'll find everything, with proof or references, in this book. If you don't want to buy it, find it in the library or for low prices on ebay or just borrow it from someone. It addresses most of the questions you asked above.

*edit*: And is there _really _a column of water in natural ponds that sucks nutrients down to the bottom? Does water really *permeate *downwards to the center of the earth, carrying nutrients with it? This is one thing you've mentioned in *every *post above, but I've never heard of it. I thought water just sits there in ponds and lakes, and particles of organic matter or sediments start to collect on the bottom surface, adding nutrients to the soil that way.


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## Jimbo205 (Feb 2, 2006)

Whatever you do, do NOT get an undergravel filter. I do not truly understand why but it DOES NOT WORK. I had one in my tank for years because I falsely believed that this was good and natural for my plants' roots. Just the opposite. When I FINALLY tore up my tank - which I HATE to do, everything I had been told was true. (I just wish they had given a GOOD explanation for WHY!). My Java Fern had grown very well on the edges of my tank, away from my undergravel filter. If I were to guess, I think it has something to do with the root hairs on the plants. But again, I do not truly understand yet. 
High tech is easy, natural is hard. I wish it was the opposite. High tech says purchase this product, follow the directions, and watch it work. Natural says read my book, pray to God that you understand or remember everything in biology or chemistry, throw some dirt and fish food and sit back and drink a beer. 
Someday I hope to switch from supplements to natural. But for all the fish food I added to my tank - I ended up with a snail explosion. 

Good luck with your aquarium. Just stay away from the undergravel filter. Someone else may be able to tell you why. I am just sharing my experience. 

On a natural tank, if it is 10 gallons or larger, do you need a filter (canister or hang on back) in the summertime or no? (In the winter, I figure for circulating heated water it would be necessary in the frigid northeast.)


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## sb483 (May 29, 2006)

Jimbo205 said:


> On a natural tank, if it is 10 gallons or larger, do you need a filter (canister or hang on back) in the summertime or no? (In the winter, I figure for circulating heated water it would be necessary in the frigid northeast.)


A filter promotes water movement, which brings nutrients to the plant leaves quicker. In the natural method, the filter has no carbon or anything else inside, it just circulates the water.


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## Glouglou (Feb 21, 2006)

*Tanks evryone*

Tank's Jimbo, I find this excellent article on substrate at

They talk about Roots hair:


> Roots and Root Hairs
> 
> "Most rooted aquatic plants have been found to possess root hairs, and several different species have been found to develop*mycorrhizal associations much the same as terrestrial plants do. Rooted aquatic plants are well adapted to growing in an anaerobic substrate. They are able to 'pump' enough oxygen to the roots so that in many cases the oxygen actually diffuses into the surrounding sediment. They can also respire anaerobically if necessary and produce lactic acid or ethanol instead of CO2 as a byproduct. The root*meristems (growing tips) of some species are even inhibited in the presence of oxygen."


And it get sense, that only by gravity the water (and nutrients) will sip trough the substrate without the need of UGF or anything else + the UGF will prevent the root hair to form, Hum!

Ok guys and girls, I surrender...
:yield:

Gone the UGF ....

And I think I will buy the book of Diane (what is the best or latest version??)
and I was thinking to buy another more on the High tech side, like Amano, what is the best in this category????


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## dwalstad (Apr 14, 2006)

Jimbo205 said:


> On a natural tank, if it is 10 gallons or larger, do you need a filter (canister or hang on back) in the summertime or no? (In the winter, I figure for circulating heated water it would be necessary in the frigid northeast.)


For summertime, the only reason you'd truly need water movement would be if the fish weren't getting enough oxygen. Check on fish in early morning (before daylight and photosynthesis starts) when oxygen levels would be at their lowest. If the fish are gasping at the surface, I trust you'll know what to do. 

There' no way to predict which tank will need water circulation or not. Some will...Some won't.


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## JERP (Feb 4, 2003)

Another thing to consider is that your substrate will compact much more quickly with a UGF. The UGF will draw water and sediment into the gravel, eventually clogging it. Regular gravel siphoning is required with a UGF. Eventually, very little circulation will occur as the substrate gets more and more compacted. The soil compaction and reduced circulation will hurt both your plants at both the above and below the soil surface.

Siphoning the gravel can damage plant roots and should be done carefully, if at all. I just graze the surface of the gravel with the siphon and poke it with a stick a bit like you would for a soil aerator for your yard.


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## Jimbo205 (Feb 2, 2006)

I try to leave my 'black gold' alone by the substrate unless I absolutely have to. I even raised my filter tube on my 27 Gallon Tank so that I filter the water and do not suck up the 'good stuff' that waits on the bottom for the plants to 'eat' it up. 

Diana, I tried being generous with the fish food, and in both tanks now have a snail EXPLOSION!!!! How does an El Naturale hobbiest deal with this? Do the shells of dead snails provide calcium in the substrate for the plants to 'eat' later? (And what is dolomite?) I have also put my 10 Gallon Tank in front of my West Window hoping the 'solar eclipse' would be good for my Dwarf Sag and Java Fern. (The Rotala Rotundifolia Green is like Superman - always!) This solar eclipse will not harm the Java Fern will it? 

From the look of the snail eggs laid, I am about to have the 2nd wave of SNAIL EXPLOSION anyday now. What do I do?


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## Glouglou (Feb 21, 2006)

*To Dwalstad*

I quote myself:


> And I think I will buy the book of Diane (what is the best or latest version??)
> and I was thinking to buy another more on the High tech side, like Amano, what is the best in this category????


I have access to Chapters in Montreal...

• This is another question for you, but I will start a new thread with this name *( Water movement or not?????*
It's about water movement... It seem that the natural way do not encourage a good water movement???
What are the reason behind this when we know that good water movement will decrease the Prandtl boundary and permit the plants to suck up more nutrients from the water column and a higher redox will decrease the availability of algae (and plants) to process iron and other metals, help the nitrifying bacterias doing their work with nitrite and producing CO2 (in the surface soil and filter mass) and keep our fishies in a conscient state.


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## Jimbo205 (Feb 2, 2006)

> decrease the Prandtl boundaries and permit the plants to suck up more nutrients from the water column and a higher redox will decrease the availability of algae (and plants) to process iron and other metals, help the nitrifying bacterias doing their work with nitrite and producing CO2 (in the surface soil and filter mass) and keep our fishies in a conscient state.


 I understood everything except the first 4 words, WHAT??? #-o


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## Jimbo205 (Feb 2, 2006)

I can tell you that I shut off my filter for one day with my 10 gallon tank and moved the last fish to another tank. I refilled my Nutrafin CO2 ladder with fresh supplies (yeast, baking soda, sugar and lukewarm water) the night before. 
When I came home yesterday, I was amazed. 
All my plants were pearling and bubbling tiny streams of (Oxygen, yes?).
I have NEVER seen this happen in my tank with water movement from my filter. 

Please share the scientific reasons for this, in both detailed and 'lite' terminology if you can. Thanks.


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## Glouglou (Feb 21, 2006)

*Sorry Jimbo...*

Sorry, my english is not that good (and my french either) and for some reason the spell check do not work on my computer???

*Kids stay in school*


I edit my post, you are suppose to read


> decrease the Prandtl boundary


The Prandtl boundary is an unstear layer around any object in water. In the case of plants this layer have to be penetrate by the nutrients in the water column to be available by the plant. Less water circulation around the plant mean thicker layer and more difficulty to used the nutrient, more circulation equal thinner layer and better absorption of nutrients.


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