filtration… do we know what is really needed???

[Magnum Man39 154]

of coarse the type of fish, and the fish density have a lot to do with this… but I’m questioning, if your fish aren’t “dirty” do you really need mechanical filtration???

I have several small tanks, that just have basic sponge filters, and they appear fine, all also have a lot of plants…

it would seem that with the correct amount of plants, and water flow, weather air or impeller powered, even the elimination of sponges could be acceptable, that a normally stocked tank, with lots of plants, and water movement would be fine… the nitrifying bacteria is on most all surfaces , including on the plants…

I realize “plants” is a pretty general word… I use many terrestrial plants rooted in the aquarium… my aquatic plants are generally anubias, and java fern, but I also have several mosses thriving in smaller tanks, plants that act as the best at filtering, are generally aggressive growing plants like vines…

it’s amazing all the “consumable” junk kits include for new aquarists to keep their filters running at “peak” performance… things like carbon… with standard water changes, and the plants I use, there has been no carbon, in any of my dozen or so tanks, for many years…

a lot of people don’t like air stones, and I’m not a fan of “normal sized” stones but I have several highly planted tanks, with 10 inch air bars in them, that I could likely shut the mechanical filters off, with no ill effects…

anyone else have thoughts on filtering???

 

[Back in the fold]

Some fish are just plain dirty . The dirtiest fish I have and have ever seen are my Fundulopanchax gardneri . They do nothing but eat and they crap like German Shepherds afterwards . The sponge filter does nothing to get the turds out . I siphon them out with water changes . This is where my bare bottom aquarium is nice . Filters fulfill their biological filtration duty and sift out suspended matter but they don’t get the sinkers . Filters also remove and detoxify dissolved gases but you are left picking up the yard just like you do with a dog .

 

[TwoTankAmin33]

You guys need to have a read here: https://www.swisstropicals.com/library/aquarium-biofiltration/

Here are the final two paragraphs.

What does that mean for aquarium biofiltration?​

Water filtration is teamwork by the members of the substrate microbial community from all domains of life. This is an important conclusion, both for freshwater and marine habitats. The different players form a food web, where most organisms cannot exist alone but are interdependent. The microbial community varies greatly depending on the availability of foods, pore sizes, and substrates. Soil biofiltration is therefore very plastic, meaning it can cope with a variety of conditions. However, one feature is common. Natural layers of biofiltration are usually undisturbed for longer periods of time (many weeks and months). In nature, no one squeezes out the debris or rinses the media on a weekly schedule. Occasionally, seasonal floods or rains may “wash” a gravel bed but regular rinsing of the filter media is not happening. The microorganisms eat the debris and the sludge is completely broken down into gases and soluble products that then escape the pore space. Soil biofilters are almost maintenance-free. The released substances are either getting into the atmosphere or are taken up by plants.

For aquarium biofiltration to be most effective, filters should be running undisturbed for as long as possible. Filter media that remain passable and have a variety of pore sizes are best. Given that we like to influence the water parameters depending on the species we keep, and thus make water soft, hard, etc, the filter media should be chemically inert, so that it does not affect the water chemistry by itself.

Author © Stephan M. Tanner, PhD

 

[Rusty_Shackleford38 154]

I think we are only beginning to scratch the suave of understanding filtration.
I've recently read some studies that are not yet published and the findings are very interesting. It basically stated in an average aquarium bacteria are pretty much evenly distributed between the filter media and global surfaces ie glass, plants, gravel, hardscspe etc. However the substrate only contains useful bacteria to a depth of about 4" which is fine because who has more than 4" of substrate anyway?
Now here's where it gets interesting. At a very high flow rate, like 4000 gph. 99% of nitrification occurs in media and not on global surfaces. Because flow brings oxygen and nutrients to the bacteria, they can grow to a greater density than on global surfaces. I know none of us are going to pump 4000 gph through a 40 gallon tank. But we don't have to. As long as we have flow, an equilibrium will be achieved between the media and global surfaces to accomplish our nitrification needs .

 

[TwoTankAmin33]

When it comes to the nitrifiers they will not be found very deep. Usually there is insufficient oxygen for them by the time the substrate is 1 inch deep. Below that there will be anaerobes.

The exception to that would be in soome planted tanks where there are the right species of plants in the substrate. Most suchj plants have t alot of their roots below an inch and thus in areas with no O. However, certain species will actually trans port oxygen down to their roots and release it. This creates an aerobic zone which allows nitrifiers to function. What is even more interesting is when this happens there will be zones above and below such an area where denitrification happens.

Petersen Nils Risgaard-, Jensen Kim, (1997), Nitrification and denitrification in the rhizosphere of the aquatic macrophyte Lobelia dortmanna L., Limnology and Oceanography, 42, doi: 10.4319/lo.1997.42.3.0529.

Abstract​

Nitrogen and O2 transformations were studied in sediments covered by Lobelia dortmanna L.; a combination of 15N isotope pairing and microsensor (O2, NO3−, and NH4+) techniques were used. Transformation rates and microprofiles were compared with data obtained in bare sediments. The two types of sediment were incubated in doublecompartment chambers connected to a continuous flow-through system.

The presence of L. dortmanna profoundly influenced both the nitrification-denitrification activity and porewater profiles of O2, NO3−, and NH4+ within the sediment. The rate of coupled nitrification-denitrification was greater than sixfold higher in L. dortmnanna-vegetated sediment than in bare sediment throughout the light–dark cycle. Illumination of the Lobelia sediment reduced denitrification activity by ∼30%. In contrast, this process was unaffected by light–dark shifts in the bare sediment. Oxygen microprofiles showed that O2 was released from the L. dortmanna roots to the surrounding sediment both during illumination and in darkness. This release of O2 expanded the oxic sediment volume and stimulated nitrification, shown by the high concentrations of NO3− (∼30 µM) that accumulated within the rhizosphere. Both 15N2 isotope and microsensor data showed that the root-associated nitrification site was surrounded by two sites of denitrification above and below, and this led to a more efficient coupling between nitrification and denitrification in the Lobelia sediment than in the bare sediment.


It used to be possible to read this paper for free without having a credential based account, Not any more. However, you can read Dr. Hovanec's presentation discussing the paper on his site, It will give you a decent summary of the article free.
https://www.drtimsaquatics.com/aqua...ticles/aquatic-plants-and-the-nitrogen-cycle/


Also, the bacteria lives inside a medium it creates which lets them attach to surfaces. Other bacteria and Archaea live there as well. However, when there is sufficient flow this film can be detached and allowed to go where ever it is carried. As noted above, the bacteria will always thrive in the greatest numbers where it gets all the things it needed delivered. If one runs a bare bottom tank there will not be any nitirifiers living in substrate, They could be found in other places, but they do not thrive in direct light. So, if they are on plants, rocks. wood or fake decor, it will be on them where they are sheltered from too much light.

Most filters are not clear walled containers. Some are tinted and others totally block out light in most of the filter. Sponge type filters have the bacteria inside them out of the light not on their exterior surface.

 

[AJ356]

I place no importance at all/significance on what, if any nitrifying bacteria there are on the surfaces and substrate. Tried this a few times. Even in a very mature tank, try taking your media out of your filter, leave the filter running for flow and oxygen levels, and see how much good the nitrifying bacteria on surfaces and substrate do in terms of ammonia and nitrite processing. Nothing, or next to nothing.

That's my findings anyway, yours may differ.

I've also tried using very mature gravel as a filter media (swapped out the existing sponge media) and the results are about the same as having no media at all, in terms of ammonia and nitrite processing.

What I am saying is not so applicable to undergravel filtration and heavily planted tanks where other things are at play for ammonia processing.

 

[TwoTankAmin33]

Here is what I know. For 6 years I ran a zebra pleco breeding tank. It was a 30 gal. breeder tank. That is basically 36x18x13 inch tank (LxWxH).

The tank was bare bottom and filled with wood, rocks, slate and caves. It was filtered with an AquaClear 200gph (now called a 50) loaded with two AC sponges with a piece of floss between them. It had a H.O.T. Magnum using the Micron Caretrdge and I customized it. The filter hung on the back left end of the tank. The output was a spray bar which ran across the top left end back to front and stopped an inch or two short of the front glass.

The intake was connected to a hose which ran the length of the ran from the left end to the right end of the tank along the rea5/bottom glass. When it reached the right end, a 90° elbow let the intake rune across the right bottom end of the tank. This was an ATI pre-filter sponge intake. Finally, there was a small power head on the left end with an ATI pre-filter. The return flow was directed across the bottom so that it ran across the caves arrayed down the bottom glass.

The tanks was originally set-up for other plecos which included a pair of zebras, a couple of L66, a pair of L333 and a pair of P. compta aka leopard frog pleco. I referred to this tank as my "Yipes Stripes" tank. When I acquired my proven breeding colony of 12 adult zebras and 5 of their offspring, I sold the 3 pleco pairs in the tank but kept the 2 zebras which got moved into the tank with a pair of discus. Yhe omco,ming colomy then went onto the now empty tank.

This tank was cyled without fish initially and then stayed cycled for the next 16 years until the zebras were gone. At the first fry hunt in the zebra tank there were 53 offspring. Another 15-20 had already been pulled to a grow tank.

There were only 4 places in that tank where there were bacteria in any numbers. The AC filter sponges and the two ATI prefilter sponges.Rhe plumbed H.O.T. Magnum held a clean Micron which got changed every 2 or 3 weeks. This was a mechanical filter inside so the ATI pre-filter was where any bacteria would be hosted. The powehead had only the pre-filter. But, those two prefilters had to be decently rinsed every week to prevent their clogging. This made the foams a poor place for the bateria to live to a decent extent.

The final place there would be bacteria in the tank was on the wood, rocks and caves whereever the surface was out of any direct light. Given how often the intake sponges were well rinsed, they were not a stable place for bacteria to live. But, for sure they did host some amount. Most of the filter based bio-filtration was in the AC foams and then on all the decor in the tank.

I lost only one adult fish in that tank over the 16 years it held zebras. Over 500 offspring came out of that tank.

That 30 breeder had to have a fair amount of its nitrifying bacteria on the decor as was in the potential media. When I had 13/20 tanks dedicated to plecos, most had sand bottoms and air powered filtration. The media was almost all 20 ppi Poret foam- cubefilters in 9 tanks, Matten filters in 3 and that zebra tank. In the 12 with Poret foam I worked to keep most of the bacteria in the foam as opposed to the sand. I did this because they had only an inch of sand which I deep vucuumed almost weekly. This tends to kell of some number of the bacteria which might be there. But cleaning the sand never eliminated all of the bacteria it hosted.

Most of the bacteria in the sand or filter foam that was lost would be replaced by those still in the tank multiplying. This effectively was in the media moreso than in the sand. This kept most of the bacteria in the media as opposed to the sand. Here is what I have learned over the past 25+ yeaes I have kept fish.

1. The bacteria will live in the greatest numbers where what they need is reliably delivered to them.
2. This will always be out of direct light.
3. Bacteria will be found in bio-media in a filter as long as the media is not allowed to clog up.
4. The amount of bacteria in any tank is the direct result of the amount ammonia being created in that tank.
5. When the over all bio-load in a rank increases or decreases, the amount of bacteria will increase or decrease accordingly. This happens via the rate at which they reproduce and/or die.
6. One can control, to a great extent, where in a tank that the bacteria generally should be found.
7. Plants, done properly, can be the best filtration one can have. They use ammonium- NH4.
8. The best filtration when one has no plants is bio-media with a decent pore structure. The more massive this can bet, the better.
9. The bacteria use ammonia (NH3) or nitrite, inorganic carbon, oxygen and a few minerals. They work better in warmer rather than colder water,
10. There are also ammonia oxidizing Archaea in most tanks which work in very similar ways as the bacteria except the Archaea use copper where the bacteria use iron. The Archaea are more photosensitive than the bacteria.
11. The bacteria can work in water with an acid pH but will do so differently than when the pH is closer to neutral or is more basic.
12. No fish have ever died from ammonia or nitrite poisoning during a fishess cycle.!

 

[plebian]

You guys need to have a read here: https://www.swisstropicals.com/library/aquarium-biofiltration/

Here are the final two paragraphs.

This is the argument for UGFs. Simple, reliable, effective...no cleaning necessary.