A bottom of the tank Matten filter?

[gardenman]

Another batch of baby Super Red plecos have emerged from the pleco cave and joined the ten-gallon tank. They're new this morning. I've seen about ten to twenty at a time so far. More are likely hiding out here and there. Suffice to say the new filter isn't discouraging the pleco breeding. They're all over the place. Most will likely get chomped down by a swordtail, but a few may survive. The plecos seem very happy with the new filtration setup. That's two pleco spawns in about seven weeks or so. The survivors of the first spawn (I've seen four or five at a time so far) are now about 3/4" to an inch long now and growing well. They're about twice the size of the new ones. The older babies are getting very bold now and stay out most of the time. They're big enough now not to get eaten too easily.

[gardenman]

Another Saturday and another update. Both tanks are continuing to behave perfectly. The green water in the ten-gallon tank has resolved on its own. (It always does given enough time.) The Aponogeton Crispus that I've had in ICU in that tank in its own little soil filled container has apparently died. I'm still giving it a couple of weeks in case there's any life left in the roots. It arrived in horrible shape and never got better. Any hope that it was just melting appears to have been just that, hope. The fish are all doing great though. There are two spawns of baby Super Red plecos in the ten-gallon tank now. Both are doing well and somehow avoiding swordtail predation. About half of the pleco fry appear to be albino which is interesting. None of the parents or grandparents were albino, so I'm not sure where that's coming from.

The Matten filter sponges are just filled with life. I was down on the floor examining the twenty-high on Thursday and took a closer look at the sponge and I was impressed by the life inside it. The sponge up against the glass gives you a nice look at what's going on and there's a lot of life living inside the sponge. There are a variety of worms, nematodes, or worm-like things. Smaller moving things that aren't worm-like, and more. It's a jungle of life inside the sponges. That abundance of small life may be encouraging the plecos to spawn. (Not that they need a lot of encouragement.)

The Water Sprite has completely taken over the ten-gallon tank and needs to be thinned. The plants in both tanks are doing well though. The sponge as a substrate doesn't seem to be impeding them at all. There have been no fish casualties in either tank in the last week. The water chemistry is still good. I'm looking at the test strip from the ten-gallon tank as I type this and the readings are all good with nitrates between 25-50. The KH is slowly climbing due to the crushed coral that's been added to the box filter. 

The snail population in each of the Matten filter tanks is still down substantially from my substrate filled tanks. There are still some snails, but maybe a tenth of what I had before switching. I don't consider that a problem though. The empty snail shells continue to pile up, but I'm leaving them for the calcium they leach back into the water. 

All in all, no problems, complaints or real issues. Everything's going great.

 

 

[HH Morant]

Thank you for the update, Gardenman! Looks like your idea is working.

On the aponogeton crispus, maybe it is in a dormant stage, I don't have any aponogeton yet, but I understand they can shut down for weeks or months at a time.

I am really coming to better appreciate your swordtails. Are they pineapple? Neon?

[gardenman]

They're neon swordtails. Or my version of neon swordtails anyway. They're neat little fish. I'm up to my eyeballs in them, but I like them. They breed true, breed readily, and are very hardy. They have some interesting personalities. There's a small male who hides out behind a sponge filter that the gals prefer over the other males, and he'll dart out, service them, then go back into hiding until another willing gal comes along. The other males are dominant, but the gals like him more.

[HH Morant]

On 1/29/2022 at 11:14 AM, gardenman said:

They're neon swordtails. Or my version of neon swordtails anyway.

They are beautiful fish, @gardenman. Seeing your swordtails is making me consider using them as a way to bring more movement and color to my tanks, which feature angels.

And you never run out of swordtails..

[Torrey]

On 1/29/2022 at 7:53 AM, gardenman said:

None of the parents or grandparents were albino, so I'm not sure where that's coming from.

The joys of double recessive traits😅

[anewbie]

On 1/18/2022 at 9:20 AM, Odd Duck said:

@gardenman I’ve been following along and I’m considering doing this in a couple tanks.  I think it’s a great idea and it’s terrific to find out others have also used the idea successfully, too.  I think the foam is likely a better filter than gravel and here’s why.  Aquarium gravel is good, finer gravel is better, but foam beats gravel, especially 30 ppi foam.  The fact that this looks like fine black sand substrate is a massive bonus as far as I’m concerned.

 

I said this earlier in the thread; but I want to repeat it; my concern is the foam will clog over time; we are not talking about days or weeks or even a month; but what happens after 6 to 12 months. You can't easily clean the sponge without tearing up the tank so you have to consider what happens when the sponge does clog....

[Torrey]

On 1/29/2022 at 10:56 PM, anewbie said:

I said this earlier in the thread; but I want to repeat it; my concern is the foam will clog over time; we are not talking about days or weeks or even a month; but what happens after 6 to 12 months. You can't easily clean the sponge without tearing up the tank so you have to consider what happens when the sponge does clog....

I have used foam on the bottom of tanks in smaller areas, but still used in such a way that taking it out was a pima.

A strong suction on a python can pull sand and mulm through a sponge... just like my pond pumps pull debris through sponges, until water flow is reduced and I use a water vac to suction the foam sponge clean. 

@gardenman, you can even test the theory once you get some mulm under the UGF. Use your camera to record from underneath the tank (if possible) to see how much mulm is pulled up into the python. 🤷‍♂️

[gardenman]

On 1/30/2022 at 12:56 AM, anewbie said:

I said this earlier in the thread; but I want to repeat it; my concern is the foam will clog over time; we are not talking about days or weeks or even a month; but what happens after 6 to 12 months. You can't easily clean the sponge without tearing up the tank so you have to consider what happens when the sponge does clog....

I have two plans in place should this happen. The obvious one is to use a gravel vac pressed tight against the foam to suck debris from the foam and unclog it. Option two is to backflush the foam by using a reverse-flow powerhead on one tube (or just pouring water down it) and blocking the other one. (Maybe leave the other tube unblocked initially to flush out any sediment from under the filter plate then once the flow is clear block it.) With nowhere else to go the water will either float the foam (not ideal) or backflush the debris out of the foam. Conventional Matten filters have been known to go for years without any servicing. This is a bigger version of a Matten filter so it's not unreasonable to assume it'll go even longer.

An interesting question is what happens to the tank if it clogs? Does the cycle crash? Does the part of the foam with no flow become an anoxic region? (Not necessarily a bad thing.) Do you even need significant water flow through a thick foam Matten filter? Does just the surface of the foam have enough bacteria to maintain a tank? I've seen some Matten filters with a very slow bubble rate for the lift tube. In nature water is flowing over the substrate more than through it. Also, the life I'm seeing in the foam in the form of various worms or worm-like critters might help to keep it unclogged.

I'll figure out what happens down the road, likely well down the road. For now, it's working well. If need be, the sponge can always be removed and cleaned. It's not much different from removing any substrate for a thorough cleaning.

[OnlyGenusCaps]

On 1/30/2022 at 8:01 AM, gardenman said:

An interesting question is what happens to the tank if it clogs? Does the cycle crash? Does the part of the foam with no flow become an anoxic region? (Not necessarily a bad thing.) Do you even need significant water flow through a thick foam Matten filter? Does just the surface of the foam have enough bacteria to maintain a tank?

Not only do I love this experiment and idea in general, I also am impressed by your dedication to learning about it in the long-term, and not just as a quick lark.  I look forward to the weekly updates, and I will be following this thread as long as you experiment continues.  I know I've said this earlier in the thread, but thank you again, so very much, for sharing this process with us all!  This thread epitomizes what I love about this forum - creative ideas explored in an open and supportive environment.  This is how the hobby advances.  Well done! 

[gardenman]

On 1/30/2022 at 9:28 AM, OnlyGenusCaps said:

Not only do I love this experiment and idea in general, I also am impressed by your dedication to learning about it in the long-term, and not just as a quick lark.  I look forward to the weekly updates, and I will be following this thread as long as you experiment continues.  I know I've said this earlier in the thread, but thank you again, so very much, for sharing this process with us all!  This thread epitomizes what I love about this forum - creative ideas explored in an open and supportive environment.  This is how the hobby advances.  Well done! 

I've been keeping fish for over fifty years now and I've tried just about everything that's come along at one point or another. I've used box filters, HOBs, UG filters, fluidized bed sand filters, k1 filters, canisters, diatom filters, sumps, and probably more that I've forgotten. This is something new (in this form anyway) that makes sense and so far anyway, is working.

If I could find a more affordable UG filter grid for my fifty gallon tank (36" X18") I'd switch that one over too. (The only one I've found is $50+ up to $65 which is kind of pricey for a chunk of plastic.) I might splurge on that at some point though.

This is just one of those "Why wouldn't this work?" ideas that had me puzzled. The answer, so far anyway, is that it does work. I can't foresee any obstacles that can't be overcome. The only way I'll find issues is by trying it. Now, for some fish that might eat the foam it wouldn't work, but for my fish, it's working well. All of the biofiltration in the ten-gallon is now done by this filter. The twenty-high goes all Matten next weekend. So far, so good though.

[OnlyGenusCaps]

On 1/30/2022 at 8:52 AM, gardenman said:

The answer, so far anyway, is that it does work. I can't foresee any obstacles that can't be overcome. The only way I'll find issues is by trying it. Now, for some fish that might eat the foam it wouldn't work, but for my fish, it's working well. All of the biofiltration in the ten-gallon is now done by this filter. The twenty-high goes all Matten next weekend.

This, to me, seems like the sort of idea that comes from someone with a wealth of experience.  So, I'm not surprised by your depth of knowledge.  I've mentioned somewhere, but I'll admit to here again, that I'm totally stealing this concept for my over engineered QT tank I am putting together right now.  It seems like the perfect solution for that, although I'd be following this thread regardless.

On 1/30/2022 at 8:52 AM, gardenman said:

k1 filters

As a quick aside, when you have time, would you be willing to share your experience using K1?  I am planning on using it in a sump chamber that is in the works, and would be curious about your thoughts.  Thanks! 

[gardenman]

K1 filtration works great.  Most filtration methods work well. Keeping the K1 in motion constantly is important and also being able to see and easily remove any sediment that should settle in the K1 chamber is helpful. In a sump you're apt to get some gunk in the corners or center of the K1 chamber. Gunk isn't necessarily bad but in a K1 type sump filter getting to it can be challenging if you want it gone.

[anewbie]

On 1/30/2022 at 8:01 AM, gardenman said:

I have two plans in place should this happen. The obvious one is to use a gravel vac pressed tight against the foam to suck debris from the foam and unclog it. Option two is to backflush the foam by using a reverse-flow powerhead on one tube (or just pouring water down it) and blocking the other one. (Maybe leave the other tube unblocked initially to flush out any sediment from under the filter plate then once the flow is clear block it.) With nowhere else to go the water will either float the foam (not ideal) or backflush the debris out of the foam. Conventional Matten filters have been known to go for years without any servicing. This is a bigger version of a Matten filter so it's not unreasonable to assume it'll go even longer.

An interesting question is what happens to the tank if it clogs? Does the cycle crash? Does the part of the foam with no flow become an anoxic region? (Not necessarily a bad thing.) Do you even need significant water flow through a thick foam Matten filter? Does just the surface of the foam have enough bacteria to maintain a tank? I've seen some Matten filters with a very slow bubble rate for the lift tube. In nature water is flowing over the substrate more than through it. Also, the life I'm seeing in the foam in the form of various worms or worm-like critters might help to keep it unclogged.

I'll figure out what happens down the road, likely well down the road. For now, it's working well. If need be, the sponge can always be removed and cleaned. It's not much different from removing any substrate for a thorough cleaning.

My guess is you would get anaerobic pocket. I know with the matten filters i use (the ones in the corner of my tanks); the only way to clean them is to remove them and run pressure water through them with lots of squeezing (we are talking about doing this for 15-20 minutes to get them clean); python isn't going to help at all; but sitting on the bottom there might not be enough current flowing through it to generate the same level of debris i see.

On 1/30/2022 at 9:38 AM, gardenman said:

K1 filtration works great.  Most filtration methods work well. Keeping the K1 in motion constantly is important and also being able to see and easily remove any sediment that should settle in the K1 chamber is helpful. In a sump you're apt to get some gunk in the corners or center of the K1 chamber. Gunk isn't necessarily bad but in a K1 type sump filter getting to it can be challenging if you want it gone.

That is the problem with K1 it only works with a good mbr that does an excellent job of circulation. Also K1 is strictly biological filtration where sponges are both biological and mechanical so really apple to oranges. 

[HH Morant]

I think getting a biological filter really clean is bad because it means cleaning away the gunk where a lot of the beneficial bacteria live. If foam is used for biological filtration, it is generally best to use foam that is course enough (30 ppi) that it does not clog easily and can be left in place for months without cleaning. But the cleaning should just be an un-clogging, not a thorough cleaning.

One of the interesting things about this experiment is that 40 ppi foam is being used. While 40 ppi might clog too readily in a canister or sump, the flow rate with an under-gravel filter is slower, so maybe that will make the difference. 

Cleaning the foam in place (rather than taking it out) would be best, and @gardenman has plans for that. We'll have to see how it works. Because getting the foam perfectly clean is not the goal, maybe it will.

@gardenman, I appreciate the idea, the effort, and the reporting. Thanks.

[gardenman]

I don't see clogging being a big issue. The ten-gallon tank has been set up so about eight weeks now with lots of messy fish getting lots of food. There's no noticeable debris, other than empty snail shells, in or on the sponge. A mulm buildup under the filter plate could be occurring, but the foam looks pretty much new. I don't see where it's going to be vastly different than any UG filter media. It's definitely not clogging on the top. Any mulm/gunk is apparently moving into and through the foam since its not sitting on top of the foam. The slots in the UG plate are bigger than the foam pores, so if it gets through the foam it should go under the UG grate. Is a mulm build up there bad? Eh, maybe. Maybe not. We'll have to see. It should be flushable from there if it causes trouble.

[gardenman]

Another Saturday and the same old, same old. Everything's good. No issues. I've got lots of baby plecos in the ten-gallon tank and they're all doing great.  No issues with the ten-gallon tank at all. The green water has cleared. The Water Sprite needs thinning which I probably will do later today. The Aponogeton Crispus is still a goner. It was pretty much dead on arrival, so it not thriving isn't a revelation. The fish are thriving. The tank parameters are all good. No problems. 

The twenty is doing well also. The portion of cryptocoryne lutea I put in there has finished melting and is now growing and looking good. I've got to sneak some more plants into that tank. I may raid my plant storage bin and see what I've got. Some of the thinned out water sprite could end up there.

No issues, No problems. It's working exactly like I'd hoped it would work. I'm watching a handful of baby plecos munching away on the leftover green beans as I type this. It's a good system.

 

[Odd Duck]

That’s a fast return to growth for a melted Crypt. lutea!  Always a good sign for the tank.

[gardenman]

On 2/5/2022 at 3:22 PM, Odd Duck said:

That’s a fast return to growth for a melted Crypt. lutea!  Always a good sign for the tank.

Yeah, I divided the plant that came into two sections and both are putting out new growth. They're doing very well. Two new leaves on the one in the twenty, and three new leaves on the one in the thirty-high. I wasn't sure how the one in the foam would do, but so far so good.

[eatyourpeas]

On 2/5/2022 at 2:43 PM, gardenman said:

Yeah, I divided the plant that came into two sections and both are putting out new growth. They're doing very well. Two new leaves on the one in the twenty, and three new leaves on the one in the thirty-high. I wasn't sure how the one in the foam would do, but so far so good.

Looking good!

I am finding my crypts and other plants that decide to "float" are attaching themselves to the Matten wall and sending roots to the back side of the wall! The wall is definitely a nutrient bank! 😍

[HH Morant]

@gardenman, there is now an article at aquariumscience.org dedicated to you and your bottom-of-the-tank Matten filter. The author (Dave) thinks it is a great idea:

2022-01-24 Added an article on “8.7.7. Bottom of Tank Matten Filter”

Today in the comments:

Dave says:

In reply to Scott …. It has a very large surface area and void volume. So under “normal” circumstances it wouldn’t plug up. The rate of decomposition of the “brown gunk” would be greater than the rate of deposition. But there are extreme circumstances which could change that. A food with low protein content, very heavy stocking, heavy feeding, low aeration, no good inoculate during cycling: can all combine to create plugging. But it has to be extreme. And yes, plants will root in it but as long as the tank is reasonably stocked, reasonably fed with a high protein food, properly inoculated and reasonably aerated one does not need to worry about plugging. I go into this in greater depth in this article https://aquariumscience.org/index.php/18-5-heavy-stocked-maintenance/

Scott Mitchell says

Hi Dave,
The bottom of the tank matten seems like a great biofilter but unlike an under gravel would it not plug up eventually?
I just can’t see how it could not. Could you explain why it wouldn’t or is this just considered ‘ok’ and just needs maintenance? I just would not want to take the whole thing out to clean it up and reinstall, especially if plants have rooted in it!
Thanks.

Edited February 8, 2022 by HH Morant

[gardenman]

Neat! Yeah, it was just one of those ideas that made too much sense. It's working well, the fish are happy, the plants are happy, it just works. I couldn't think of a reason it wouldn't work and it's worked fine since the end of November when I started it. The amount of life in the foam is impressive. There's all kinds of stuff living inside the foam. There are no indications it's clogging. It just works. It's cheap, easy and pretty much foolproof.

[Torrey]

On 2/8/2022 at 2:48 PM, gardenman said:

Neat! Yeah, it was just one of those ideas that made too much sense. It's working well, the fish are happy, the plants are happy, it just works. I couldn't think of a reason it wouldn't work and it's worked fine since the end of November when I started it. The amount of life in the foam is impressive. There's all kinds of stuff living inside the foam. There are no indications it's clogging. It just works. It's cheap, easy and pretty much foolproof.

I'm now looking for large sheets? Blocks? Of black matten foam.

I very much want to try this!!!

[gardenman]

Another Saturday and the same old same old. The tanks are both doing great. No issues. No problems. The parameters are good. Everything's going as expected. Well, the baby plecos in the ten-gallon are far more numerous than I'd thought, but other than that everything's going well. I thought only four or five had survived the first spawn. It turns out to have been more like forty. They were just hiding out and now that they're bigger and more confident they're everywhere. There seem to be even more from the second spawn, so yeah, I won't have a shortage of plecos for a bit. For whatever reason, the swordtails in this tank don't prey on the baby plecos. The first spawn is now about an inch long and they're out a lot more. The second spawn are smaller in size, but there seem to be more of them.  So, I'm up to my eyeballs in Super Red plecos.

I thinned out the Water Sprite earlier in the week, but you wouldn't know it now. It's growing very, very well in the foam. The Cryptocoryne Lutea in the twenty-high is doing very well also. It's not growing as fast but as the Water Sprite but is past the melting stage and has four new leaves.

I've only got a photo of the ten-gallon tank this morning as I was too lazy to go out and shoot the twenty high, but both are doing very well. I'm throwing in a bonus photo or two of the baby plecos in the ten-gallon too. They're happily munching on the green beans from this morning's feeding.

 

[Torrey]

On 2/12/2022 at 7:57 AM, gardenman said:

Another Saturday and the same old same old. The tanks are both doing great. No issues. No problems. The parameters are good. Everything's going as expected. Well, the baby plecos in the ten-gallon are far more numerous than I'd thought, but other than that everything's going well. I thought only four or five had survived the first spawn. It turns out to have been more like forty. They were just hiding out and now that they're bigger and more confident they're everywhere. There seem to be even more from the second spawn, so yeah, I won't have a shortage of plecos for a bit. For whatever reason, the swordtails in this tank don't prey on the baby plecos. The first spawn is now about an inch long and they're out a lot more. The second spawn are smaller in size, but there seem to be more of them.  So, I'm up to my eyeballs in Super Red plecos.

I thinned out the Water Sprite earlier in the week, but you wouldn't know it now. It's growing very, very well in the foam. The Cryptocoryne Lutea in the twenty-high is doing very well also. It's not growing as fast but as the Water Sprite but is past the melting stage and has four new leaves.

I've only got a photo of the ten-gallon tank this morning as I was too lazy to go out and shoot the twenty high, but both are doing very well. I'm throwing in a bonus photo or two of the baby plecos in the ten-gallon too. They're happily munching on the green beans from this morning's feeding.

 

ORD 😍