What is this about no filter?

[eltylT]

On another earlier post the topic of filter-less tanks came up and I really want to learn more about this. All responses welcome.

[wgoldfarb]

Since nobody had chimed in, I'll take a first shot. I believe Byron's mention of no filtering on the other thread refers to planted tanks. Since plants absorb ammonia, nitrites and nitrates, a heavily planted tank (emphasis on heavily), in theory, doesn't need supplemental biological filtration.

In terms of mechanical filtration I'm not as clear, but from what understand plants also help in this regard. In theory, any solid waste produced by fish will go into the substrate and provide added nutrition for plants. I'm guessing you night need something like a Malaysian trumpet snail or shrimp to help this process, but this is just guesswork on my part.

I don't know if you would still need some way to ensure good water flow inside the tank.

[eltylT]

Oh ok now I get it . Ill do some searching and see what I come up with. Thanks again

[~firefly~]

Plants will do fine without a filter - but there should still be circulation of some kind. Often, the heater alone will produce enough just from heat rising through the water column, but you can develop dead spots that have the potential to encourage stagnation. Water changes are still a must in these set ups. If you're considering trying this I'd be interested to read how you get on.

[Byron]

As I raised the topic, I'll start off here.

Diana Walstad is a name known to many; she is a microbiologist who several years ago began writing articles (and a book) on "natural" planted aquaria. She advocates a substrate of 1 inch of clean soil capped by 1+ inches of clean sand or fine gravel. Lots of plants, and moderate fish load. No filter. No regular water changes.

Many have done this and it does work. But, there are real risks. I'll continue on the filter issue, leaving aside everything else.

Obviously one can have fish tanks with no filters. For decades before electricity people kept fish in tanks. And many do so today, including myself in one "experimental" 10g. Live plants are nature's filters, and frankly, they do the job better, all else being equal. But with lots of plants there are few fish. I recall one author who said an aquarium could be self-sustaining if it was a 55g tank, well planted, with a group of 6-8 tetra as the sole fish load. Most of us want more fish than that. And more are possible, up to a point.

Diana refers to her tanks as moderately stocked, and I've not seen exact numbers. I absolutely will not forego water changes, every week, 1/3 to 1/2 the tank volume. Doing this obviously allows one to have a few more fish. When I had my 10g experiement, it had one inch of play sand, lots of plants, and a heater. No filter and no light (it sat right next to a west-facing window and I was anxious to see how the plants would respond with no artificial overhead lighting). The fish included 9 pygmy corys, 11 Boraras brigittae (one of the "dwarf" rasbora), a dwarf puffer and two shrimp. The puffer and shrimp were not intended, they arrived with the corys in the bag, so in they went as I had no other suitable tanks for them. Also, lots of snails, mainly Malaysian Livebearing with a few bladder/pond snails [I have snails in all my tanks, I just add some and let them do what they want]. I fed the fish normally. This tank ran for around six to eight months with no problems, other than some algae on the back glass (against the window, not surprising) and a very small bit of cyanobacteria now and then also at the back. I did a 50% water change every week.

I had two issues with this tank. One was the lack of overhead light. This not only made it very difficult to observe the fish, as they were always against the light source; it also meant that the plants all grew toward the back (light source). The second issue was the not-quite clear water. The water was clean, but not crystal clear. The light issue may have had something to do with this too. Anyway, after several months, I moved it away from the window, and added a sponge filter and overhead light. It ran for many months thereafter. Here are some photos of it. First is initially, no light/filter. Second, a month later with the floating plants changed and with an overhead light just to make it clearer to photograph. Third is what it turned into, exactly one year later, and after I added the light and sponge filter.

10g July 1-10.JPG10g Aug 19-10 (2).JPG10g July 31-11.JPG

I like a filter primarily to move water around. I will never use chemical filtration, since this competes with the plants and will remove essential nutrients, especially dissolved organics which are a prime source of CO2. Biological filtration is not necessary with plants, so I don't encourage it. It is obviosly present in the filter, just as it is throughout the tank on every surface. And when I rinse/wash my filters, be they the sponge filters every week at the water change, or the canisters every 2-3 months, I do so under the tap. There is no need for "bacteria" for nitrification with plants, and besides there are more bacteria in the substrate than the filter.

Byron.

[eltylT]

Thank you Byron . If the plants grow well enough and I can maintain it long enough , the 30 gallon rebuild will be my experiment of tank with no filter . I'll keep it updated in the journal . Tanks again and I'll talk to ya later.

[Cliff]

The key element for your success using the Walstad method (just as with with any other set-up) will be with your research before you set-up your tank.

It can be easier to set-up a aquarium with a appropriate filter, cycle it, and safely add your fish. Using the Walsted method requires a large focus on the plants and balancing the needs of the plants with the bioload of the fish. Depending on your experience level, I would suggest to take this approach cautiously and not rush into it

[Byron]

Yes, I agree totally. One thing I'm not clear on, eltylT, is...are you intending soil under the sand substrate, or are you just going to do a tank with no filter? Soil is not "necessary" and I wasn't sure if I may have made that clear before, or got things confused. Soil is a very different ball game, and carries some very significant issues.

Byron.

[eltylT]

Thanks for your concern Cliff , but this will be done slowly over time after a whole lot of serious research. I don't intend to rush into it , and I'm sure I can acquire the info needed to make this tank a safe place for all involved . Byron the substrate is layer of the Just Natural brand of natural compost cow manure , with a lite dusting of Miracle-Grow bone meal , and this is topped off with a layer of playsand . The sand was washed or should I say rinsed over and over several times for nearly 30 mins. before being added to tank . No plants yet , I'm waiting for the smaller particulates to settle as much as they will . All material for substrate was purchased at Lowes . Will you elaborate on the issue of using soil or does compost and sand warrant anything different. eagerly awaiting KNOWLEDGE , I appreciate all the help I can get.

[talldutchie]

Anyone interested in this subject I would advice to read Diana's shrimp bowl project:
http://www.atlasbooks.com/marktplc/00388Shrimp.pdf

I've tried this myself and found it can be made to work but I would advice a semi-shaded spot and a lamp instead of the spot on the window sill I chose. Even so when we tore it down this weekend we found that the three shrimp were still alive.
If you got something lying around to get some water movement so much the better.
A shrimp bowl can be done at minimal cost and with bits and pieces many of us have at hand.