HMF Questions

[Mol_PMB]

I've made several HMFs with the jetlifters and foam from fishphilosophy and am very happy with them.

[bekateen]

Hi TTA,

Thanks for the personal experience story re: clogging and not clogging. I am basing my concern simply on what others have written elsewhere in the forum, but assuming you keep some hearty wood eaters, then I think the occasional vacuuming should be sufficient to keep the HMFs running for months at a time, if not longer.

My primary concern has been the chewing, and I think some kind of plastic grill would be more than sufficient without impairing function.

I've visited the swisstropicals website several times and read its materials, but I've held off on buying any HMFs until I could sort this out to my own satisfaction.

Cheers, Eric

[TwoTankAmin]

eric-

I do not keep the messy wood eaters. My wood does make most of the mess in tanks, but nothing like the wood eaters can generate. But, no matter what filter setup one uses, I would bet those fish tax it. The advantage to using the HMF is not only its volume, but its massive surface area. It is a lot easier to clog the surface of almost any other filter than an HMF. Even if clogging is an issue, it will happen way less often. So I think you are correct that the only issues is pleco chewing.

Like I said, drop Dr. T. and email, he will answer. If I were going to the NJAS event next Thursday where he is a speaker, I would ask him for you. Unfortunately, I decided to pass since I am going to another event in a few weeks where he is giving the same talk plus another. There will be a lot more time to talk with him then as it is a full weekend event. If you can wait until early April, I am happy to discuss it with him then.

[bekateen]

Thanks TTA,

I'm in no rush, but I will be setting up a new tank, likely to be a 75 gal, in April or May.

I have messaged the guy at Swiss Tropicals before but he didn't respond to my message- people are busy and it probably slipped through the cracks of time.

Cheers, Eric

[pleconut]

If I get round to setting up a Panoquolus species tank, using one of these filters before you get round to the 75 gal, I'll let you know how I get on.

[TwoTankAmin]

I finally grabbed a few shots of my HMF setups. Here is the 3 inch 20 PPI in the tank I have with tons of wood viewed from the dirty front side and then the end against the front glass. It is dirty (note it uses a DIY return spraybar):

Here is he tank with the twin Mattens at each end and then a close up of the return which uses a pump but then the output is a powehead piece. Also shown is the spraybar I DIYed for the return:

I hope this helps folks with ideas for their own setups.

Last comment- in smaller tanks such as a 20 long with an HMF I use the standard Jetlifter and an air pump. The pumps I am using with the others are Eheim Compact Hobby pumps- the smaller models which have flow controls.

[2wheelsx2]

I like the spray bar idea but I would guess that you would need to use a water pump to drive it and not an airpump, which would really reduce the usable size of a 15 gallon.

[TwoTankAmin]

You are correct that a pump requires more space behind the foam. I use a pump/spraybar in spawning tanks because the fish are adults and they need lots of oxygen in the water. In smaller tanks for growout I am fine with air power. Also, with the dual design the 2nd return is intended to create flow across the cave mouths. As a result, the return is completely submerged and does not do anything much to help with oxygenation. I have other grow out tanks which use only Poret cubes run on air power.

The goal is to match the type of filtration with the purpose of the tank.

The main advantages to using Poret are its quality and specifications which create the second major benefit, they do not need to be cleaned as often as other filter media. This reduces my workload which makes it worth every dollar spent on this media. I tend to rinse the ATI sponge filters weekly and the Poret cubes only every 3-4 weeks. Mattens can go a whole lot longer without needing maint.

[2wheelsx2]

Yes I use a powerhead and a second airstone even in my fry tanks to get the oxygenation going in the tank. Would have to try this in a 40 gallon. Thanks for the details.

[Narwhal72]

Starting in October last year I started switching out my 20 ppi foam that I had in my central system with the 10 ppi foam. It made a huge difference in reducing clogging from pleco poop. Tanks that would clog up almost to overflowing in a week now take about a month to clog up and rinse out clean much quicker.

My 20ppi foam was moved into individually filtered 10 gallons with airlifts that I use for breeding corys and tetras. So far I have not had to clean out any of the foam in these tanks for clogging. Many of them are covered in java moss and java fern that has rooted itself to the surface of the foam.

I am very pleased with the decision to switch out to the 10 ppi with my plecos. My central system has a number of Panaque and Panaqolus in it along with lots of wood.

Andy

[TwoTankAmin]

Wow- I have had several Mattens in place in pleco tanks for month and only had to clean one. I only clean the Poret cubes in pleco tanks every 3 weeks or so. I use almost exclusively 20 ppi. Most are 4 inch cubes, but I also have a couple of the 5 inch which I clean less often. Where I use Mattens, they are the sole filter on a tank.

I have only one complaint about the cube and jetlifters. After in use for a while they clog. The air flow gets reduced. They are easy to clean but if one fails to do it, you will find the air flow suddenly stops completely. It is important, when cleaning the tube, also to remove the gray air collar and clean it as well.

[pleconut]

Thanks for letting us know, I gather you've been doing some tank maintenance.

[bekateen]

Wow- I have had several Mattens in place in pleco tanks for month and only had to clean one. I only clean the Poret cubes in pleco tanks every 3 weeks or so. I use almost exclusively 20 ppi.

But if you don't have wood-eaters, you may not experience the debris buildup at anything close to the rate possible with Panaques and Panaqolus.

Cheers, Eric

[Jobro]

I have panaqolus in 2 tanks, both with HMF.

No eating of any sort at the hmf. Neither P. Albivermis nor P. Maccus sp. I never even worried about that to be honest.

But you really need low PPI like 10-20(max) for all that poop.

My 400L Community was running on HMF for more than a year, no cleaning ever needed. Though it was/is kinda overstocked. Now with 7 (young) Albivermis in there it started clogging very rapidly. Had to take it out and clean it. Was a real mess! No fun doing that!!! Since I don't want to do this more often in the future, I added a canister filter with it's inlet in front of the HMF, so hopefully most of the poop will end up in that one rather than in the HMF.

If I would set up a panaqolus tank right now, I probably would use something like a low throughput, air driven HMF filter and a second high throughput filter. Maybe even with the second one being a HMF style high throughput filter as well, but with two sheets of 1-2" 10PPI and another sheet of 1-2" 20PPI behind. And make it so I can remove the first sheet of 10ppi easily, clean it, and put it behind the second sheet of 10PPI, in fact switching positions of the 10PPI sheets and have them rotate whenever cleaning is needed. And using something like that for the throughput: http://www.amazon.de/TUNZE-6015-000-Tun ... B0054S8NNE
Cheap, high throughput, low power consumption, also acceptable silent.

I'd probably go with similiar approaches for any new Pleco tanks I'd set up in the future. One slow for bioreactions and another fast, high troughput for clean water, oxygenation and water movement. I'm going with only HMF in my current pleco tanks and I'm not really satisfied with the outcome.

[bekateen]

Good to know, jobro. I may be setting up a 75 gallon tank soon for either 5-10 Panaqolus or 3-6 Leporacanthicus heterodon, and I'm strongly considering an HMF filter for it. But if Panaqolus, I'd still probably mount a rigid screen in front; my maccus and albomaculatus chew on everything! LOL

Cheers, Eric

[TwoTankAmin]

You guys do know that you can use multiple sheets in a Matten? Instead of running a 3 inch 20 ppi you could run a 2 inch 10 ppi followed by a 2 inch 20 ppi. The two sheets of foam can be set up touching each other or with a space between them.


The way the Matten is supposed to work in terms of organic waste is that it is getting broken down into ever smaller particle sizes as it moves deeper into the foam. By the time they work their way out the back they are extremely fine and used up a lot as well. We see this as the bits of mush on the bottom glass behind the foam that I suck up in 60 seconds every week. Any finer, and the particles recirculate into the water and get removed via water changes. I am amazed at how clear my water is in tanks with Mattens and Poret cubes. I used to think only floss or micron filter carts would keep water that clear.

[bekateen]

You guys do know that you can use multiple sheets in a Matten? Instead of running a 3 inch 20 ppi you could run a 2 inch 10 ppi followed by a 2 inch 20 ppi.

Hi TTA,

Maybe you missed it, but yes. That's what jobro described in his post, and what I am considering. Although, I wouldn't use an air lift, I'd power it with a recirculating pump... And also have additional recirc pumps in tank for aeration and water current ( always good to have a backup aerator in tanks, IMHO).

Thanks,
Eric

[Jobro]

You guys do know that you can use multiple sheets in a Matten? Instead of running a 3 inch 20 ppi you could run a 2 inch 10 ppi followed by a 2 inch 20 ppi. The two sheets of foam can be set up touching each other or with a space between them.

Yeah, in my first HMF I ever build, I used 2cm 20PPI and 3cm 30PPI behind each other. I'll try to add a picture for everyone.

It worked fine for more than one year, until the first panaqolus moved in. It clogged really fast and the HMF was not able to collect all the new panaqolus poop form the tank. The whole bottom of the tank started to get covered in panaqolus poop. I had to clean it. I never had to do this before, but after 3 months of panaqolus pooping the water level behind the hmf was so low, the whole hmf began to bulge in by the water pressure. Now i just have to clean the canister every 2-3 weeks, which is way more easy than cleaning the HMF in a huge planted tank.

On my Panaqolus Maccus sp. tank I only used one sheet of 3cm 20ppi and it always gets clogged after some weeks. It's easier to clean it in a small tank though.

[TwoTankAmin]

I would think for the panaqs you would go with a 10 and 20 in terms of ppi?

eric- I did the same until it dawned on me I could make another matten at the other end of the tank and use it both as a filter and a circulation pump. See my poasts in page 2 of this thread.

When you think about it, the more massive the filter foam can be, the more amazingly well it can work. I look at a 12.5x12x3 foam in a 33 gal tank vs what I used to have with a hang-on and a powehead with a big Hydro Sponged intake. The matten.cube filters tanks are cleaner and the maint. routine is about 1/3 the time.

I only use air power for Mattens in 20 longs and for the Poret cubes. I use small pumps for the rest.

[bekateen]

On my Panaqolus Maccus sp. tank I only used one sheet of 3cm 20ppi and it always gets clogged after some weeks. It's easier to clean it in a small tank though.

Jobro, I would expect that a 3 cm thick HMF would be too thin to really be effective, considering that other people here are using HMFs up to 3 inches thick (~2.5 times thicker), sometimes more.

eric- I did the same until it dawned on me I could make another matten at the other end of the tank and use it both as a filter and a circulation pump. See my poasts in page 2 of this thread... I only use air power for Mattens in 20 longs and for the Poret cubes. I use small pumps for the rest.

TTA, yes I recall those posts, and I'm considering that option also. I'm talking about putting this in a 75 gallon, 4-foot-wide tank, my biggest yet if I get to go through with the setup, potentially full of panaqolus... Lots of wood poop needing lots of decomposition!

Cheers,
Eric

[Jobro]

The guy that invented HMF in Germany Hamburg in 1996 wrote on his website, that only the first 2-3cm are really active and the rest is not doing very much.

I believed in him and went for 3cm as a minimum. No idea if thicker filters would help. Thicker ones should clogg up even more by my logic, as less dirt will fall behind the filter but be stuck inside the filter. The thinner I went the less it clogged on me. You are free to make some experiments yourself. I just don't think anything more than 5cm will have any bilogical effect, but some mechanical. And by filtering mechanical, it will have to clogg at some point(whereelse should the debris go inside the filter?). I don't want this to happen at all though. That's why I'm going with thinner ones, in hope of less clogging.

Fact is I have been using HMFs on 12 tanks simultaneously, only 2 of them had 5cm, all the other had 3cm. It worked for everything except panaqolus (where 5cm clogged faster than 3cm). I even have some 3cm 60PPIs running on dwarf Cory tanks, no clogging. 60PPIS is like super tight. It's like a common kitchen-sponge. But I wouldn't recommend it for anything but super low level "waste" tanks. Works fine with pygmy, hastatus and habrosus. Doesn't even work for a shrimp tank on the other hand.

30PPI seems to be nice for everything else except panaqolus. 20-10PPI should be tested for panaqolus, maybe with different strengths.

with 3cm 10PPI in front of 3cm 20PPI it might be enough to just clean the 20PPI every once in a while and have the 10ppi with all the active bacteria going nonstop for years without any cleaning at all.

Though, like TTA wrote, it might be way easier to maintain with a single 3-5cm 10PPI (that hopefully will never clogg) and just remove all the debris behind it by siphoning it once every while. This is the way it's meant to be. No cleaning of the filter needed for years, just siphoning out the piled up bioload behind the filter. But, with 20PPI, this does not seem to work for panaqolus. Maybe with 10PPI?

I don't think a thicker filter will prevent clogging. Only lower PPI can do this.

[bekateen]

Since I haven't used HMF yet, I can't comment from experience. But what was written earlier (in this thread, or maybe in another on this site) - if I understood correctly - is that the thicker the foam, the more anaerobic a place you create at the inner most layer, so denitrification can start to occur. Maybe two pads 3 cm each as you mention will suffice for this, but I can't imagine one 3-cm pad doing so.

[TwoTankAmin]

It is important to be aware of what goes on inside a big thick Matten setup. So I would like to quote from Dr. Tanner's site:

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.

from http://www.swisstropicals.com/library/a ... iltration/

So, if one has a lot of waste, as with wood eating plecos, the solution is to have both a substantial amount of media but also to have multiple porosities involved. What is going on inside a Matten is a process. It starts with larger bits and pieces of organic material. The larger this stuff may be or the more of there is, the more important "staging" becomes. Big pieces enter and what emerges out the back is very tiny pieces and gasses. As the original big piece of waste is attacked by an assortment of microorganisms, it is broken down and its components become food for the microorganism. Each time this piece of waste is broken down a bit, it becomes smaller and will move deeper inside the filter.

We tend to think of filtration only in terms of nitrification. This is a mistake as there is a lot more going on. Read some studies on this topic and what you learn is that in lab experiments where they start with basic water, a bit of carbonate and ammonia and nothing else, the result is many types of microorganisms begin to appear. Something as basic as the natural cell deaths of the nitrifiers creates organic waste in the "system." This then begets heterotrophs which go to work on the organics. The end result is starting with only the basic nitrification parameters and microorganisms, suddenly there is a mixed community.

The implications of this are what Dr. Tanner wrote, a properly configured set of media will result in filtration that comes close to what nature provides on its own. This is not an easy concept for most hobbyists to wrap their head around. For decades we have been sold smaller filters with minimal media. These work great for nitrification, for setting up to remove the trapped wastes as we do when we rinse media, for helping with circulation and gas exchange. If one has only a few tanks, this sort of setup is fine, especially if they are not large tanks.

Using a Matten, either as a sheet or as a corner filter setup, changes the whole filtration paradigm. Firstly, the flow rate through a Matten is a whole lot slower than other filters. Next, the amount of available surfaces for bio-film to colonize are maximized. Then there is the combination of thickness and volume. All of this combined results in something unlike almost any other filter in the hobby.

As eric noted, denitrification can even come into play. As water passes through the foam, and thus the bio-films inside, the microrganisms do their work. And if one part gets a little clogged, there are myriad other routes the water can take. But what also happens is that the small amount of denitrification which occurs in any established biofilm can become a much greater factor. It isn't that there are large anaerobic pockets inside a Matten. Rather, there are areas where the water that reaches them has first traveled over and through other spaces where all of the oxygen is basically used up and what remains is nitrate. In an area where this happens, the denitrifiers will multiply. This doesn't mean that all the water coming out of the back side of a Matten is anaerobic, far from it. What it does mean is the amount of nitrate in the water will be much less than were the same tank filtered in more traditional ways.

The best configuration for any given Matten filter will always depend on the specific tanks and stocking. A perfect example for me is using Poret foam in a canister. I use Eheim Pro IIs. These were made in two sizes. One has two media baskets and the other has three. In the smaller one I have 100% 20 ppi foam but in the bigger one I have the first basket with 10 ppi and the next two with 20 ppi. But, I am not working with the wood eating plecos.

I would suggest that there are two ways one can approach this. First, is what I mentioned above, use two foam sheets starting with a 10 ppi followed by a 20 ppi. But one can achieve somewhat similar results simply by using a single, thicker, 10 ppi foam. However, one should be aware this will change what comes out the back of the Matten setup. When an organic particle is broken down, it will release out of a 10 ppi foam sooner than from a 20 ppi. In the dual foam example that piece of waste has to work its way through the smaller 20 ppi pores before it can emerge. Bear in mind that those organic particles being broken down provide nutrition for many of the organisms living in the bio-film which are not limited to nitrifiers.

I think when it comes to the big waste producers, a certain amount of trial and error is needed. How thick should the 10 ppi be vs the 20, how thick should the setup itself be. The one thing that is certain when it comes to a Matten, or any tank filter for that matter, is that the bigger the media is, the more effective the setup will work and the less often it will need to be cleaned.

I have not mentioned some of the finer ppi foams one can use- 30 and 45 ppi. These really are either good in a big filter setup where one may hve a 10 ppi followed by a few 20 ppi and then end with a 30 ppi. This will give one maximal filtration capability. But trying to use only a 30 or 45 ppi foam in anything but a shrimp or fry tank is likley to have it clog fast. Small size wastes works fine with smaller pore sizes but will just clog in other applications.

I think if I were trying to do a Matten in a panaq tank I would want to start with 3 - 4 inches of 10 ppi followed by a similar amount of 20 ppi, perhaps even more. I also think I would be inclined to use a sump setup rather than in the tank if I were working with the larger species. The one drawback to an in Tank Matten is the reduction in volume for the fish. Rather than reduce the amount of living space in the tank I would move the filtration out of the tank entirely and into a sump.

As with everything I write, this is just one man's opinion, and there is always more than one good way to do almost anything in a tank and usually there are several functional solutions.

[Jobro]

Since I haven't used HMF yet, I can't comment from experience. But what was written earlier (in this thread, or maybe in another on this site) - if I understood correctly - is that the thicker the foam, the more anaerobic a place you create at the inner most layer, so denitrification can start to occur. Maybe two pads 3 cm each as you mention will suffice for this, but I can't imagine one 3-cm pad doing so.

I understand where you are going with this. True. You need an anaerobic environment to get to the denitrification.
That's the actual point of going with HMFs.
The idea behind HMFs is not to force anaerobic reactions by pushing water through a fat layer of aerobic reactions until all the O2 is gone. This is how denitrification in a high flow filter works (if it works at all), aka a canister etc.
HMF is meant to be a low flow filter. As any Biofilter has to be.
The water should be flowing at around 5-10cm/minute through the HMF. (imagine 5 cm per minute, that's pretty damn slow in my eyes! Like a snail moving.) A little more or less won't hurt at all. These are just vague guidelines for an optimum.
Test showed, that there was almost no difference in biofiltration going from 3 to 5cm at those water speeds. There is some tiny benefit, but actually not worth the effort of going for anything more than 5cm. Anaerobic reactions do happen in the first 2-3cm already, at those speeds.
Big surface -> slow flow -> high biological activity

At those speeds, there is so much bioreaction in the first few cms, there is nothing much left to happen afterwards. Anything added will just be for mechanical filtration, which can or can not be a good thing depending on your preferences.

Sorry the site is german only: http://www.deters-ing.de/Filtertechnik/Mattenfilter.htm
This is the first available scientific/technical work on HMF available and is the baseline for any HMF in it's original purpose. Sure you can build high flow filter with fat "matten" as well, but that won't be a HMF.

TTA was faster with his reply. A lot of very good stuff he got there! Especially important is the part, the longer it runs the better it goes. Not Cleaning is better than cleaning in bio filters. keep that in mind.

But I can't really agree with TTAs input on thicker mattens will help here though. Bigger surfaces with bigger structures(less PPI) is certainly going to help with clogging. That's right. 100% agreeing with that. But panaquolus poop will clog the 20PPI matten at some point I'm 100%positive. The fatter the matte, the more likely to clogg in my eyes. You can in no way compare normal fish waste with that stuff those panaqolus tend to produce. Panaqolus owners will know.
I just can't see much of an advantage in fat mattens, they will soak up more debris. But you can't really get it out of there. It will be stuck until it's clogged. Once it's clogged, it will be more work to clean a fat matten than a thin one. Thin mattens will not take up that much debris, so more of it will be lying behind the "matte". You can just siphon it out. And I am 100% positive the endproduct lying behind a 5" matte is going to be the same as behind a 1-2" matte. It will just be less, because more of it will be stuck inside the fatter matte.

[bekateen]

I just can't see much of an advantage in fat mattens, they will soak up more debris. But you can't really get it out of there. It will be stuck until it's clogged. Once it's clogged, it will be more work to clean a fat matten than a thin one. Thin mattens will not take up that much debris, so more of it will be lying behind the "matte". You can just siphon it out. And I am 100% positive the endproduct lying behind a 5" matte is going to be the same as behind a 1-2" matte. It will just be less, because more of it will be stuck inside the fatter matte.

This is where I will bow out and let you experienced HMF users work it out. But I will make two comments as I go: (1) I agree with you that a thicker piece of foam will be more difficult to rinse clean because debris in the center of the mat will be difficult to flush out. (2) (this is a question, nit a comment) if the decomposers can break down nitrogen to N2 gas, will other decomposers not also successfully break down the plant fiber/sawdust poop to CO2?

Thanks, Eric

P.S., regarding TTA's comment to use a sump instead of putting the HMF in the main tank, if I'm going to do that, I'll have to learn how to set up and use a sump first.

[dw1305]

Hi all,
I'm not a

Panaque

keeper, but the saw-dust and faeces they produce doesn't have a high bioload, quite the opposite. The wood in both saw-dust and faeces (because in both cases that is what it is, just smaller bits of wood) has a really high carbon to nitrogen ratio (~250:1 C:N) and the structural carbohydrates in wood (principally lignin) have evolved to be both water-proof and resistant to decomposition.

Personally I'd syphon the wood waste it out from in front of the filter wall, but that is a largely on grounds of aesthetics, rather than its pollution potential. It will impede flow if it builds into a thick layer, but it can only build into a thick layer because it is very slow to decompose (it has negligible BOD <http://www.planetcatfish.com/forum/view ... nd#p261810>).

I like poret PPI10 foam foam for an HMF, a good thick rigid sheet, and I planted both top and tank side, after that I pretty much left it alone. I'm with Dr Tanner, I'm a believer in "good things come to those who wait", and that a diverse array of micro and meso-organisms brings resilience. If you have areas with different flow speeds through the filter wall that is an advantage, not a disadvantage, because they will support different assemblages of organisms.

I'm not really bothered whether anaerobic de-nitrification does, or doesn't, occur in the centre of the filter plate. HMF's are different from other filters, I don't see any problem with aerobic nitrification and anaerobic de-nitrification occurring simultaneously within the filter sponge, there is a large surface area exposed to atmospheric and dissolved gases and gases will continually diffuse into, and out of, the sponge along their diffusion gradients. I am still going to make try and keep levels of dissolved oxygen near to saturation in the tank water, because oxygen is the prime metric in biological filtration, and high levels of oxygenation allow your tank to deal with unexpected pollution events.

De-nitrification is of limited use to me, I have planted tanks, so build up of NO3 isn't a problem.

cheers Darrel

[Jobro]

I am pretty sure the panaqolus poop will be decomposed at some rate. This rate might just not be fast enough for most HMFs. Speaking, more poop coming in than can be decomposed in the same time. It will add up and clogg.

Throwing fatter matten at it won't solve that. Creating a bigger surface to take on more poop in "parallel" might solve it on the other hand. fatter mattens will mean more serial decomposing. It will be in order. New stuff can only be decomposed when the old is gone. Using bigger hmfs (bigger in term of length and width) with lower PPI on the other hand will enable it to take on more poop at the same time and there will be more time for it to be decomposed.

It's like an entrance to a big festival. No matter how long the hallway behind the entrance might be, only a certain number of people may enter at the same time.
You have to widen the entrance to the point all people can walk in simultaneously to prevent big waiting lines.

Maybe you would have to install the HMF on the back of the tank rather than on one of the sides to create enough surface for panaqolus poop to be decomposed in a proper fashion. Maybe using multiple mattens behind each other can solve it as well. But I doubt such a constellation would run for more than 1 year without maintenance and that's what an HMF is supposed to do. Maybe the HMF principle just won't work out for panaqolus at all, as Darrels insights on wood decomposition would point to. As it won't decomposit fast enough it will end up clogging.

[bekateen]

Yeah, don't get me wrong, I'm not looking for a "maintenance-free" solution, there is no such thing in captivity. At the very least I'd still be vacuuming and water changing on schedule. I'm just wondering if there is a better way to run the filtration system with the rare cleanings required by HMFs with fish like Panaqolus, since half of my plecos are in that group, and I'm planning to add more.

It's okay for now, I don't even own the tank yet - planning is great and wise, but there's no reason to put the cart before the horse.

Thanks to you all, Eric

[dw1305]

Hi all,

Maybe the HMF principle just won't work out for panaqolus at all, as Darrels insights on wood decomposition would point to. As it won't decomposit fast enough it will end up clogging.

I haven't got any practical experience of this, but I think you can just syphon the wood waste out and leave the HMF to get on with it.

cheers Darrel

[TwoTankAmin]

When I suggest thicker is better for the messy fish, it implies multiple ppi sheets involved. It is important that these be arrayed from lowest ppi to highest ppi. So if you start with a 2 or 3 inch 10 ppi followed by a 3 inch 20ppi, there should be sufficient "dwell time" for organics in the 10 ppi to br broken down into much smaller particles which should not clog the 20 ppi.

If I can ever get the temporary tanks down whuch are currently blocking my access to the 125 and its sump, I would set up the poret loaded sump. This tank is for my big clown loaches etc. Not wood eaters but messy fish at their current sizes. The sump is supposed to hold 6 sheets of 3 inch thick Poret- 10,20,20,20,30 ppi in that order. They are supposed to have a 1 inch space between each sheet. Including the sump, the system will hold about 155 gals. I am hoping that I will be retired from the hobby before I need to clean those foams

That setup was laid out for me by Dr. Tanner. It is basically 15 inches of media and I do not think the 1 inch spaces will foster much gas exchange. The suggested flow rate for the sump is 400-500 gph. Consider that "conventional wisdom" suggest aquariums should have a turnover rate between 5 and 10 times the volume of water. If I followed that bit "wisdom," what was suggested is 2.7 to 3.3 times.

When talking about how thick the foam should be, I think with a quality product like Poret. That thickness is not a huge impediment to functionality. Common sense tells me this based on my last 15+ years of experience. The smaller a foam or sponge, the faster and easier it will clog. This is moreso the case when the foam involved becomes less rigid. For years I have used Hydro sponges. On occasion, when I got behind on maintenance, I would find one of these collapsed down to about 1/3 its normal size because it was so clogged. There was very little good being done by this filter.

I am not sure, but I would guess that there are two aspects to Mattens and rigid foam. The first is the surface area of the sheet mot the internal area created by the pores. The greater this area is, the harder it becomes to block inflow. We need to bear in mind that the water does not pass through the foam in a straight line, it will navigate the internal twists and turns. This also means that clogging the foam is also not so easy.

And that leads me to think that thicker is better. Of course, there is a limit to this. I could put together a bigger sump setup than above. Instead of five 3 inch sheets, I could make them all 4 inches thick or I could double the number. I doubt this would appreciably slow the system, what it would be is overkill as much of the foam would never have a chance to clog and thus becomes a waste to do. I could be wrong here.

There is another reason why a large rigid foam filter works best with a lower flow rate besides extending dwell time. As flow increases, the shear forces involved with the water moving rapidly though bio-media can cause bits or even larger pieces of the bio-film to become detached and to get blown out into the tank. The one potential downside to Mattens is they do little to help with flow and circulation in a tank. I find Myself adding a pump or powerhead to pleco tanks. I like to have current blowing across cave mouths and helping to push debris near the bottom towards the Matten.

As always how I do things here are what I feel works best for me. My way is neither the one best not the only way that will work well. Each tank has its own specific needs and how one chooses to meet these is rarely universal. We do what works best for us in any given set-up. I do not keep wood eaters so what I am suggesting is based more o theory than practice. My experience in respect to a tank that makes a lot of waste is mostly due to overstocking and not messy fish. I can correct that problem by removing fish. There is no way to make a messy fish less messy.