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Mattenfilter on Tunze pumps (two methods)

Posted: Mon Mar 02, 2009 5:45 pm
by Keith Wolcott
Tunze pumps do a great job of moving a lot of water, with little energy and heat, but they have some weaknesses that I have been wanting to improve upon. First they are not fry friendly. Small fish can be sucked in and killed. Second, in a planted tank I find that I must frequently remove small bits of plants from the intakes and from the exhaust grids. I have experimented with two different, but similar solutions to these problems.

Using 1 inch reticulated foam, glued with silicon, I enclosed two Tunze pumps with the top of the enclosure above the waterline. This is a mattenfilter as discussed in the thread called Stream(ish) project ( ... en&start=0). I obtained my foam from the source that Barsten gave the link to ( ... en&start=0). It is two inch thick foam, but I found that with a sharp knife I had no trouble slicing it down the middle to get one inch foam.


One pump inside.

With the output grids and the magnetic attachments showing. I cut the holes about 2/3 of the actual size so that they fit tightly.

It's not a very good picture of it installed, but it is the best that I have.

This has been running for several days and seems to be working great. The water level in the open part at the top is virtually the same as the tank water level which means that the pumps are not working much to pull the water through the foam. When I feed, some food gets sucked onto the outside of the foam, but the loaches come around and scour it clean. I think that this will reduce pump maintenance to almost zero.

A second version of the experiment covers a pump directly with one piece of foam and no glue.

Start with a 2 inch thick rectangular piece and a slit in the middle.

Put it on the pump. Make the slot just long enough to fit tightly.

Trim the foam.

In the tank.

I don't really know how much the flow is reduced by the foam. But feeling the current with my hand both before and after, I could not tell the difference. The above two pumps are in my loach tank. I then did the same for my hillstream river tank with a small Tunze pump (6045).

This pump moves about the same amount of water as the three aquaclear 70s that I had in the tank, but uses 7 watts as opposed to 60 watts (for three). The tank temperature in two days has dropped from 79 degrees F to 74 degrees F (from 26C to 23C).

So far I am pleased with how this is working and I think the foam eliminates the problem of having plant debris getting inside the pumps. I should only have to occasionally remove plant debris from the outside of the foam- much easier than removing and dismantling the pumps. The foam also makes these pumps fry friendly.

Which method above is better? I don't know, but I like the simplicity of the second method of directly covering each pump. It is also best for redirecting flow and for ease of removing the pumps for maintenance. I will report back after a few months of testing.

Posted: Mon Mar 02, 2009 6:38 pm
by LES..
Hi Kieth,

Personally i would go with the first option. This is purely on the basis that you will be able to judge the level of clogging in the sponge by the difference in water height between the inside and the outside of the chamber.

The second option however may give a more aesthetic look, no large block of gray in the tank. I don't see it as an issue but that is coming from the guy with a huge blue wall of sponge in his tank (-:

I hope you get the chance to run both options for a while and report back on how you get on with them.


Posted: Mon Mar 02, 2009 7:02 pm
by farid
hi keith,
i actually like the first version you cought two flies on the same clap :)

the outlets look superb and the magnetsystem to fix the filter! nice version..

i agree with LES on the second part...about having a smaller filtervloue will fill up the foam much faster...and as tunze streams dont really have much power it's a quastion of time how long they deliver the same amounth of a stream...(oxigen! )


Posted: Mon Mar 02, 2009 10:24 pm
by chefkeith
Nice modifications.

Posted: Tue Mar 03, 2009 7:31 am
by Keith Wolcott
Thanks all.

farid and LES.. I think that you are both exactly right. The advantage of the first system is that we can tell at a glance if the filter is becoming clogged. I'll have to monitor the second system carefully to learn how long it takes before it needs to be cleaned.

Mattenfilter on Tunze pumps (two methods)-2nd method failed

Posted: Sun Mar 15, 2009 7:39 pm
by Keith Wolcott
After two weeks, the first method above is still running well with no drop in water level inside the foam. The second method of putting the foam directly on the pump has failed in the sense that the flow is down to maybe 1/3 of what it should be. Thus, I have made an enclosure for the second group of two pumps similar in idea to what I did for the first two pumps at the beginning of this subject. This time it is made from a single piece of foam with no glue.

I started with a piece of two inch thick foam and cut a slit into one side. That side will be above the water level and the pumps will go inside.

Then I cut holes for the two pumps.

Inside the vents are open and should receive plenty of water.

The pump on the back.

In the tank. You can see two outputs of two canister filters coming through the foam at the top above the Tunze pumps. I first thought that these would cause problems since they were in the way, but they actually hold the foam in place quite nicely.

Now as with my two pumps on the other end of the tank, I can easily check if the water level inside the foam container is lower than the water level outside of it. If so, it is time to clean the foam. This was pretty easy to do and it keeps the pumps from clogging with plant leaves and other debris. Second it makes the tank safe for small fish and eggs. Now I just have to do a version of this on my river tank.

Posted: Sun Mar 15, 2009 10:11 pm
by Diana
It sure seems you have a lot more square inches of foam to act as filter when you do either the first version, like a column, or the flat version, compared to wrapping the pumps separately.
I am surprised at the actual results! The wrapped pumps slowed down so fast!

Posted: Mon Mar 16, 2009 8:19 am
by Keith Wolcott
Yes Diana, I actually made this last one a bit larger than I needed to, to cover the pumps, but I wanted to be sure that there is enough flow and that it lasts a good long time.

The failed method, failing so soon may be more expected if you keep in mind that these Tunze pumps have propellers that are designed to move lots of water, but are not designed to pump water against any resistance. Unlike a power head or a pump in a filter, the open design means that if there is a bit of resistance, it just swirls the water around without moving it much.

I am hopeful that the enclosures will last a good six months or more without any maintenance other than an occasional vacuuming of the outside of the foam. Time will tell. I'll report back in six months.

Posted: Mon Mar 16, 2009 12:03 pm
by wasserscheu
Excellent engineering Keith - me impressed 8)

I prefer the first method too. Your first version has lower water flow on the matt, thus allowing the bacteria easier to keep their slime coat (which makes the filter effective in the first place). To make it a perfect Mattenfilter, you could calculate the flow speed in the matt. It should average between 5 and 10meter/minute ( I think, I double-check in case of interest). That speed is found the best condition for bacteria to grow.

Keep in mind that the 1st version does not take away ANY efficiency from the pump, as the resistance inside the matt is overcome by the pressure of the water given due to height difference. That is the first very cool technical circumstance. the 2nd "very cool circumstance" ;-) is that the pressure due to water-level-difference creates a very even spread of pressure on the matt - means the water gets pressed evenly over the entire matt, rather than the water finding individual canals in the matt with the least resistance.

a lot of organisms grow in the matt an supply valuable food to certain fish. Remember "odyssey's" report of a Stiphodon surviving 3 months (or so) inside a canister filter, and it did not look starved out at all?

All above details are published by Olaf Deters in his homepage - his credit. I only tested his setup and was very pleased with the results. I have a mattenfilter in an external little tank, followed by a larger water reservoir. Once the matt get plugged (approx every 8 weeks, I just squeeze it, the mud travels to the reservoir, where it sinks to the bottom. The water in the visible system is crystal clear, partially due to the combination of Biological (matt), mechanical and gravity filter methods.

I combine the methods, as it is good to have small filter intakes as well, to more efficiently suck in floating particles. In Keith's case the Tunze is so fast, that he still gets enough suction. But a typically Mattenfilter, has that slow flow, that it takes longer to clear the water then with conventional setup.

I typed too much, sorry, I could write a summary in proper English some day :lol:

Posted: Tue Mar 17, 2009 8:13 am
by Keith Wolcott
Wolfram- Great information. Thanks for the reference to Olaf Deters home page. I knew nothing about what the ideal speed of the water through the mattenfilter should be. I have about 5 to 10 times the recommended 5-10 cm per minute recommended flow rate. Thus I may not get much biological activity. That was not my reason for adding them, but I had thought that it would be an added benefit. This gives me a lot to think about. The goal of the ideal aquarium setup is ever elusive!

Posted: Tue Mar 17, 2009 1:48 pm
by wasserscheu
You are most likely still doing better with your setup than a normal canister filter does, in re to bac. conditions. Commercial filters all run too fast and hardly anybody worries about. Bac's grow anywhere anyway, but I still am all convinced of the mattenfilter, as it provides a stable home for our "beloved" bac's.
You still may have perfect conditions directly at the most outer surface of the matt. perhaps tieing some moss or plants on it increases the effect, but makes it very complicated to clean it.

The good thing about your higher flow, is that it will suck in all floating stuff and thus be a very nice and effective filter. There is always many ways to the sausage stand.

P.S.: just figured, in case you put spacers to your magnetic holders, the surface of the usuable matt increases (as water can enter between glass and matt) and thus the water speed drops and cleaning periode becomes longer too.

Here a link that provides more detail: additionally to the german links, you find one for an English version, that TKK added on the very bottom of the post. ... ght=deters

Posted: Wed Mar 18, 2009 9:00 am
by wasserscheu
Keith, a quick thank you for posting your filter setup. It made me make a mental U-turn and opened my eyes to look for those stream pumps. I was going to buy another used canister, now I am looking for propellers only. I thought they were too expensive, due to your input I checked and they are not that expensive, thanks.

Posted: Wed Mar 18, 2009 8:11 pm
by Keith Wolcott
Wolfram- Thank you for the link with the translated information. It has made it much easier for me to understand the finer points of the issues.

Let us know what you do with your Tunze pump if you get one.

I also think that you are correct in that it is better for the foam to be away from the glass so that there is more area and also so that the loaches can clean off food that gets on the outside of the filter. I think that the first filter that I made can be pulled away form the glass a good centimeter or two so I intend to do that. The second one that I made was designed to be away from the glass and so are the last two. Pictures of one of these last two are below and are made for the Tunze 6045. They are each made from one piece of foam and only take a few minutes to make. The one pictured below is made by making a pocket in a piece of one inch think foam. For the other one I used two inch thick foam. Over the long term, I'll see which is better.

Starting with a rectangular piece of foam, cut a slit with a sharp knife into one end to form a pocket. Then cut a hole on one side for the output of the pump and a hole on the other side for the magnet attachment. I cut the holes about two-thirds of the size needed so that they fit tightly. For the Tunze pump the output hole is a little lower than the magnet hole.




Posted: Tue Sep 08, 2009 11:27 am
by Keith Wolcott
I have been running the Tunze pumps enclosed in foam for about 6 months now. I am very pleased with the results. I do not have to ever clean any debris or plants out of the pumps since the water is filtered as it enters. The foam does become saturated with small debris (which you cannot really see) and the water level inside the foam drops as much as an inch over 3 to 4 months. I find that if I use a 5/8 inch hose and siphon water to a bucket with the end of the hose moved slowly along the outside surface of the foam, it removes excess buildup. I have been doing that about once a month and this keeps the flow quite good. This is very quick and easy maintenance so i am going to stick with it. The advantages are that nothing clogs the pumps themselves, fish and eggs and fry are protected from being sucked into the pumps, and I get quite a bit of extra biological filtration in the foam (also mechanical filtration).

Since, as Wolfram pointed out above with the link to the article, biological filtration works better if the flow rate is much slower than I have, I decided to add similar foam covers to my canister filter intakes. Since their flow rate is 300 to 350 gph and I have added three square feet of surface area per filter, this will be far more optimal biological filtration. This also makes the canister filters almost entirely biological filters and the mechanical filtration is done by the foam. I am hoping that this will mean that canister maintenance will need to be done less often. I have kept careful records of how often I clean the canisters and how dirty they are so I will see how it compares. Here are the pictures of the new foam covers.

First I cut an 18 inch by 5 inch by 2 inch piece of foam.

I cut a slit with a long sharp knife down the middle of one end of the foam. I needed some way to hold it open and my wife had some old plastic rectangular grids which were used in the closet for shoes. She was getting rid of them and I had been keeping my eye open for potential ways to hold the foam open so I cut them into strips.

With the plastic brace in (and the top of it cut off). I also rounded off the corners of the foam with a pair of scissors.


Here are two of them installed next to two that are left to do. I shortened the intakes to be only about 5 inches long so that it is easier to put the foam on. I made a hole in the foam about 2.5 inches from the top, fed the intake into the hole, and slid it up to the top so that the intake holds the foam in place.

Here are all four installed. Notice the change in color on the foam covering the Tunze pumps on the right.

Here they are looking from above the water. They are about .5 inches above the water line.

Vacuuming these with a siphon hose will not be so easy, so I think I will most likely have to remove and rinse these out periodically. Since the flow is so slow and the area is so large, I am hoping that it will be able to go 6 months to a year before I have to do anything. They are also fairly easy to take off and on. I will report back when I know more.

Posted: Tue Sep 08, 2009 11:00 pm
by Diana
Good idea to have such a large intake surface.
I wonder if an easier method is to use a piece of pipe inside (where you used the shoe holder piece).
The pipe would be drilled with as many holes as you can without losing structural strength.

I use the up tube from a UGF system, and drill holes with a 1/4" bit. The holes are on 4 sides of the pipe (if you can imagine a round pipe having sides) and are perhaps 1/2" apart.

Then I cut into the sponge enough to be able to slip the sponge over the pipe.

This works well, so far, but I can see I need a larger sponge area. My sponges are also filling with very fine debris, and I am using coarse cell sponges.

Be careful lifting out the sponges; the debris falls out of them.